Cannot start WEBrick server. Mysql2 `require': cannot load such file - ruby-on-rails

I have installed a fresh install of Ruby / Rails on an clean Windows 8 install and amy getting errors when trying to start the WEBrick server. Have searched for an answer but cant find one.
Error as below:
C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/mysql2-0.3.18-x64-mingw32/lib/mysql2/mysql2.rb:2:in `require': cannot load such file -- mysql2/2.2/mysql2 (LoadError)
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/mysql2-0.3.18-x64-mingw32/lib/mysql2/mysql2.rb:2:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/mysql2-0.3.18-x64-mingw32/lib/mysql2.rb:31:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/mysql2-0.3.18-x64-mingw32/lib/mysql2.rb:31:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.4/lib/bundler/runtime.rb:76:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.4/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.4/lib/bundler/runtime.rb:72:in `each'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.4/lib/bundler/runtime.rb:72:in `block in require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.4/lib/bundler/runtime.rb:61:in `each'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.4/lib/bundler/runtime.rb:61:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.4/lib/bundler.rb:134:in `require'
from C:/Users/Brendon/Sites/quote/config/application.rb:7:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:78:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:78:in `block in server'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:75:in `tap'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:75:in `server'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands.rb:17:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
Any help greatly appreciated

You need to use bundler to install the gem first.
Either do:
gem install mysql2
or
cd /my/rails/project && bundle install
note: the mysql2 gem is a [expletive] to install... best of luck

Related

Error while running bundle install and rails server command

Whenever I try to run the above mention command it shows the following error.
This is the first step when i try to run the simple bundle command: Bundle install
/home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/digest.rb:16:in `const_missing': library not found for class Digest::MD5 -- digest/md5 (LoadError)
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/source/rubygems/remote.rb:26:in `cache_slug'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/fetcher/compact_index.rb:107:in `cache_path'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/fetcher/compact_index.rb:83:in `compact_index_client'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/cli.rb:646:in `warn_on_outdated_bundler'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/cli.rb:24:in `block in dispatch'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/vendor/thor/lib/thor.rb:366:in `dispatch'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/cli.rb:22:in `dispatch'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/vendor/thor/lib/thor/base.rb:444:in `start'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/cli.rb:13:in `start'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/exe/bundle:30:in `block in <top (required)>'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/friendly_errors.rb:121:in `with_friendly_errors'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/exe/bundle:22:in `<top (required)>'
from /home/mifi/.rbenv/versions/2.4.0/bin/bundle:22:in `load'
from /home/mifi/.rbenv/versions/2.4.0/bin/bundle:22:in `<main>'
And when i found the above error i try to run the server command for the rails but it doesn't work out for me.
rails server
/home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require': libcrypto.so.1.0.2: cannot open shared object file: No such file or directory - /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/x86_64-linux/digest/sha1.so (LoadError)
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/source/git.rb:4:in `<top (required)>'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/lockfile_parser.rb:122:in `<class:LockfileParser>'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/lockfile_parser.rb:14:in `<module:Bundler>'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/lockfile_parser.rb:13:in `<top (required)>'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/definition.rb:2:in `<top (required)>'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler.rb:129:in `definition'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler.rb:95:in `setup'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.15.3/lib/bundler/setup.rb:9:in `<top (required)>'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/mifi/huginn/config/boot.rb:6:in `<top (required)>'
from bin/rails:8:in `require_relative'
from bin/rails:8:in `<main>'
and same for the rails -v command:
/home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:120:in `require': libcrypto.so.1.0.2: cannot open shared object file: No such file or directory - /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/x86_64-linux/digest/md5.so (LoadError)
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:120:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/generators/app_base.rb:2:in `<top (required)>'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:68:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:68:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/generators/rails/app/app_generator.rb:1:in `<top (required)>'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:68:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:68:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/commands/application/application_command.rb:2:in `<top (required)>'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:68:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:68:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/command/behavior.rb:82:in `block (2 levels) in lookup'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/command/behavior.rb:78:in `each'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/command/behavior.rb:78:in `block in lookup'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/command/behavior.rb:77:in `each'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/command/behavior.rb:77:in `lookup'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/command.rb:68:in `find_by_namespace'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/command.rb:42:in `invoke'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/cli.rb:16:in `<top (required)>'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:68:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:68:in `require'
from /home/mifi/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-5.1.2/exe/rails:9:in `<top (required)>'
from /home/mifi/.rbenv/versions/2.4.0/bin/rails:22:in `load'
from /home/mifi/.rbenv/versions/2.4.0/bin/rails:22:in `<main>'
Is there anything I am missing out.
I got this same error, and it seems like that version of ruby got corrupted.
> bundle install
~/.rbenv/versions/2.5.6/lib/ruby/2.5.0/digest.rb:16:in `const_missing':
library not found for class Digest::SHA1 -- digest/sha1 (LoadError)
> ruby -r digest/sha1 -e 'p Digest::MD5'
...
Library not loaded: /usr/local/opt/openssl/lib/libssl.1.0.0.dylib (LoadError)
...
Using a mac with rbenv, I fixed it as follows:
> ruby -v
ruby 2.5.6p201 (2019-08-28 revision 67796) [x86_64-darwin18]
> rbenv install 2.5.6
...
continue with installation? (y/N) y
...
Installed ruby-2.5.6 to ~/.rbenv/versions/2.5.6
> ruby -r digest/sha1 -e 'p Digest::MD5'
Digest::MD5
bundle install worked after that.
Note: I got a lot of messages about running gem pristine, so just in case, I also ran:
> gem pristine --all
One of your underlying libraries is not installed. Run
sudo apt-get install libssl-dev libssl
Assuming you are on ubuntu linux.

`require': cannot load such file -- ffi (LoadError) `require': cannot load such file -- ffi (LoadError) when trying to start rails console

Full stack trace:
/Users/galharth/.rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:274:in `require': cannot load such file -- ffi (LoadError)
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:274:in `block in require'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:240:in `load_dependency'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:274:in `require'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/sys-proctable-1.1.1-universal-darwin/lib/darwin/sys/proctable.rb:2:in `<top (required)>'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:274:in `require'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:274:in `block in require'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:240:in `load_dependency'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:274:in `require'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/sys-proctable-1.1.1-universal-darwin/lib/sys-proctable.rb:1:in `<top (required)>'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/bundler-1.10.6/lib/bundler/runtime.rb:76:in `require'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/bundler-1.10.6/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/bundler-1.10.6/lib/bundler/runtime.rb:72:in `each'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/bundler-1.10.6/lib/bundler/runtime.rb:72:in `block in require'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/bundler-1.10.6/lib/bundler/runtime.rb:61:in `each'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/bundler-1.10.6/lib/bundler/runtime.rb:61:in `require'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/bundler-1.10.6/lib/bundler.rb:134:in `require'
from /Users/galharth/Documents/productbattle/config/application.rb:7:in `<top (required)>'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:141:in `require'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:141:in `require_application_and_environment!'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:67:in `console'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from /Users/galharth/.rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/commands.rb:17:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
Rails version: 4.2.5
Ruby version: 2.3.0
Bundler version: 1.10.6
OSX: El Capitan (Co-worker using windows)
Try running gem install ffi --platform=ruby.
See this issue for more insight and resolution options.
I was able to successfully install the ffi gem by running gem install ffi --platform=ruby, adding the line gem 'ffi' to my Gemfile, and then running bundle install`.

Error when launching a new rails app in Ubuntu 14.04

I am trying to create a new rails app on Ubuntu 14.04. This is my first time using Rails in Ubuntu, (previously developed in Windows 10). I set up the development environment, my ruby version is ruby 2.3.0p0 and rails version is 5.0.0. Once my dev environment was set up, I started a new project by typing in a terminal:
rails new MyApp
Then, I typed:
cd MyApp
bundle install
And finally, I attempted to start my rails server by typing:
rails s
Instead of the rails server starting, I get this response in the terminal:
/home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler/runtime.rb:89:in `rescue in block (2 levels) in require': There was an error while trying to load the gem 'uglifier'. (Bundler::GemRequireError)
Gem Load Error is: Could not find a JavaScript runtime. See https://github.com/rails/execjs for a list of available runtimes.
Backtrace for gem load error is:
/home/rusty/.rvm/gems/ruby-2.3.0/gems/execjs-2.7.0/lib/execjs/runtimes.rb:58:in `autodetect'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/execjs-2.7.0/lib/execjs.rb:5:in `<module:ExecJS>'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/execjs-2.7.0/lib/execjs.rb:4:in `<top (required)>'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/uglifier-3.0.0/lib/uglifier.rb:5:in `require'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/uglifier-3.0.0/lib/uglifier.rb:5:in `<top (required)>'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler/runtime.rb:86:in `require'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler/runtime.rb:86:in `block (2 levels) in require'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler/runtime.rb:81:in `each'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler/runtime.rb:81:in `block in require'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler/runtime.rb:70:in `each'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler/runtime.rb:70:in `require'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler.rb:102:in `require'
/home/rusty/Maple/config/application.rb:7:in `<top (required)>'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/railties-5.0.0/lib/rails/commands/commands_tasks.rb:88:in `require'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/railties-5.0.0/lib/rails/commands/commands_tasks.rb:88:in `block in server'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/railties-5.0.0/lib/rails/commands/commands_tasks.rb:85:in `tap'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/railties-5.0.0/lib/rails/commands/commands_tasks.rb:85:in `server'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/railties-5.0.0/lib/rails/commands/commands_tasks.rb:49:in `run_command!'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/railties-5.0.0/lib/rails/commands.rb:18:in `<top (required)>'
/home/rusty/Maple/bin/rails:9:in `require'
/home/rusty/Maple/bin/rails:9:in `<top (required)>'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/lib/spring/client/rails.rb:28:in `load'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/lib/spring/client/rails.rb:28:in `call'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/lib/spring/client/command.rb:7:in `call'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/lib/spring/client.rb:30:in `run'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/bin/spring:49:in `<top (required)>'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/lib/spring/binstub.rb:11:in `load'
/home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/lib/spring/binstub.rb:11:in `<top (required)>'
/home/rusty/Maple/bin/spring:13:in `require'
/home/rusty/Maple/bin/spring:13:in `<top (required)>'
bin/rails:3:in `load'
bin/rails:3:in `<main>'
Bundler Error Backtrace:
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler/runtime.rb:85:in `block (2 levels) in require'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler/runtime.rb:81:in `each'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler/runtime.rb:81:in `block in require'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler/runtime.rb:70:in `each'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler/runtime.rb:70:in `require'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/bundler-1.12.5/lib/bundler.rb:102:in `require'
from /home/rusty/Maple/config/application.rb:7:in `<top (required)>'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/railties-5.0.0/lib/rails/commands/commands_tasks.rb:88:in `require'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/railties-5.0.0/lib/rails/commands/commands_tasks.rb:88:in `block in server'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/railties-5.0.0/lib/rails/commands/commands_tasks.rb:85:in `tap'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/railties-5.0.0/lib/rails/commands/commands_tasks.rb:85:in `server'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/railties-5.0.0/lib/rails/commands/commands_tasks.rb:49:in `run_command!'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/railties-5.0.0/lib/rails/commands.rb:18:in `<top (required)>'
from /home/rusty/Maple/bin/rails:9:in `require'
from /home/rusty/Maple/bin/rails:9:in `<top (required)>'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/lib/spring/client/rails.rb:28:in `load'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/lib/spring/client/rails.rb:28:in `call'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/lib/spring/client/command.rb:7:in `call'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/lib/spring/client.rb:30:in `run'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/bin/spring:49:in `<top (required)>'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/lib/spring/binstub.rb:11:in `load'
from /home/rusty/.rvm/gems/ruby-2.3.0/gems/spring-1.7.2/lib/spring/binstub.rb:11:in `<top (required)>'
from /home/rusty/Maple/bin/spring:13:in `require'
from /home/rusty/Maple/bin/spring:13:in `<top (required)>'
from bin/rails:3:in `load'
from bin/rails:3:in `<main>'
My app was created successfully. All the appropriate files are located in my app's folder. I just can't seem to get the rails server to start.
I found a solution. Open a terminal and change to your app's directory. Example, type cd MyApp.
Then install the Rubyracer gem by typing gem install therubyracer in your terminal, and then add gem 'therubyracer' to your gemfile.
My rails server starts now. Thank you uDaY for helping me.

rails server error on ubuntu

I am following ruby on rails getting started guide ( http://guides.rubyonrails.org/getting_started.html )
I installed ruby and rails as it is suggested in the guide but when I try to execute:
bin/rails server
I see the following error in the terminal:
Warning: Running `gem pristine --all` to regenerate your installed gemspecs (and deleting then reinstalling your bundle if you use bundle --path) will improve the startup performance of Spring.
/var/lib/gems/2.1.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:80:in `rescue in block (2 levels) in require': There was an error while trying to load the gem 'uglifier'. (Bundler::GemRequireError)
from /var/lib/gems/2.1.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
from /var/lib/gems/2.1.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:72:in `each'
from /var/lib/gems/2.1.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:72:in `block in require'
from /var/lib/gems/2.1.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:61:in `each'
from /var/lib/gems/2.1.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:61:in `require'
from /var/lib/gems/2.1.0/gems/bundler-1.11.2/lib/bundler.rb:99:in `require'
from /home/soroosh/rails/blog/config/application.rb:7:in `<top (required)>'
from /var/lib/gems/2.1.0/gems/railties-4.2.5.1/lib/rails/commands/commands_tasks.rb:78:in `require'
from /var/lib/gems/2.1.0/gems/railties-4.2.5.1/lib/rails/commands/commands_tasks.rb:78:in `block in server'
from /var/lib/gems/2.1.0/gems/railties-4.2.5.1/lib/rails/commands/commands_tasks.rb:75:in `tap'
from /var/lib/gems/2.1.0/gems/railties-4.2.5.1/lib/rails/commands/commands_tasks.rb:75:in `server'
from /var/lib/gems/2.1.0/gems/railties-4.2.5.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from /var/lib/gems/2.1.0/gems/railties-4.2.5.1/lib/rails/commands.rb:17:in `<top (required)>'
from /home/soroosh/rails/blog/bin/rails:9:in `require'
from /home/soroosh/rails/blog/bin/rails:9:in `<top (required)>'
from /var/lib/gems/2.1.0/gems/spring-1.6.3/lib/spring/client/rails.rb:28:in `load'
from /var/lib/gems/2.1.0/gems/spring-1.6.3/lib/spring/client/rails.rb:28:in `call'
from /var/lib/gems/2.1.0/gems/spring-1.6.3/lib/spring/client/command.rb:7:in `call'
from /var/lib/gems/2.1.0/gems/spring-1.6.3/lib/spring/client.rb:28:in `run'
from /var/lib/gems/2.1.0/gems/spring-1.6.3/bin/spring:49:in `<top (required)>'
from /var/lib/gems/2.1.0/gems/spring-1.6.3/lib/spring/binstub.rb:11:in `load'
from /var/lib/gems/2.1.0/gems/spring-1.6.3/lib/spring/binstub.rb:11:in `<top (required)>'
from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/soroosh/rails/blog/bin/spring:13:in `<top (required)>'
from bin/rails:3:in `load'
from bin/rails:3:in `<main>'
I am using ubuntu 15.10 , ruby 2.1 and rails4.2.5.1
If you look closely at the error message, this is the important line:
There was an error while trying to load the gem 'uglifier'.
Uglifier is a Javascript wrapper, so it will need a Javascript interpreter. I recommend installing NodeJS:
sudo apt-get install nodejs
read more about uglifier: https://github.com/lautis/uglifier

Active_support/dependencies.rb:247 `require': cannot load such file -- 2.1/pg_ext (LoadError)

I'm using Ruby 2.1.5, Rails 4.1.6 and PostgreSQL 9.3.5 on a Windows machine.
When I try to bundle exec rails server, I end up with the following error:
DL is deprecated, please use Fiddle
c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:247:in `require': cannot load such file -- 2.1/pg_ext (LoadError)
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:247:in `block in re...re'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:232:in `load_dependancy'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:247:in `require'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/pg-0.17.1-x86-mingw32/lib/pg.rb:10:in `rescue in <top (required)>'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/pg-0.17.1-x86-mingw32/lib/pg.rb:3:in `<top (required)>'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:76:in `require'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:72:in `each'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:72:in `block in require'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:61:in `each'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:61:in `require'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler.rb:133:in `require'
from C:/....../config/application.rb:5:in `<top (required)>'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:79:in `require'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:79:in `block in server
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:76:in `tap'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:76:in `server'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:40:in `run_command!'
from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.6/lib/rails/commands.rb:17:in `<top (required)>'
from bin/rails:8:in `require'
from bin/rails:8:in `<main>'
I needed to use a newer version of pg gem:
gem 'pg', '~> 0.18.0.pre20141117110243'
After updating, sometimes happens.
Try remove all gems and install all again. like
rm -rf ./vendor/bundle
bundle install

Resources