uninitialized constant RubyVM::DebugInspector seen in official Rails getting started guide - ruby-on-rails

I am a new user to Ruby on Rails, and I've been following the official getting started.
Platform: Windows 10
Ruby 2.2.4
Rails 4.2.5.2
What I am doing:
rails new myapp cd myapp bundle install rails server
Then I get this error:
C:\Users\MyUser\AAA\myapp>rails server
C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/binding_of_caller-0.7.2/lib/binding_of_caller/mri2.rb:21:in `callers': uninitialized constant RubyVM::DebugInspector (NameError)
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/web-console-2.3.0/lib/web_console/integration/cruby.rb:28:in `set_backtrace_with_binding_of_caller'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:80:in `rescue in block (2 levels) in require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:72:in `each'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:72:in `block in require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:61:in `each'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:61:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.11.2/lib/bundler.rb:99:in `require'
from C:/Users/MyUser/AAA/myapp/config/application.rb:7:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.5.2/lib/rails/commands/commands_tasks.rb:78:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.5.2/lib/rails/commands/commands_tasks.rb:78:in `block in server'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.5.2/lib/rails/commands/commands_tasks.rb:75:in `tap'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.5.2/lib/rails/commands/commands_tasks.rb:75:in `server'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.5.2/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.5.2/lib/rails/commands.rb:17:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
I have already tried uninstalling debug_inspector and running bundle install after, but the problem persists.
Can anyone help me please?

If it is still actual. Try to add debug_inspector to your Gemfile.

You need to bundle the gem before start rails server. Follow following steps:
rails new myapp
cd myapp
bundle install
rails server

I deleted all versions of debug inspector first:
gem uninstall debug_inspector
then installed it again with the arch -arm64 flag
arch -arm64 gem install debug_inspector
For some reason, it required to install another gem (which may not be necessary for you)
arch -arm64 gem install rbs -v 2.1.0
And after that, the error has gone.

Related

Rails 4.2 web-console issue

After upgrading to Rails 4.2, I was excited to try out the newly integrated web-console, but I'm having some issues.
In the release notes for Rails 4.2, it mentions: "New applications generated with Rails 4.2 now come with the Web Console gem by default."
Since I upgraded to 4.2, I assume that means I will still have to specify it in my Gemfile. Without adding it to my Gemfile, rails just gives me "undefined local variable or method `console'" so I assume that to be the case.
Once I added gem 'web-console', '~> 2.0' to the Gemfile, and run rails server, I now get:
/home/kevin/.rvm/gems/ruby-2.1.5/gems/binding_of_caller-0.7.3.pre1/lib/binding_of_caller/mri2.rb:21:in `callers': uninitialized constant RubyVM::DebugInspector (NameError)
from /home/kevin/.rvm/gems/ruby-2.1.5/gems/better_errors-2.0.0/lib/better_errors/exception_extension.rb:7:in `set_backtrace'
from /home/kevin/.rvm/gems/ruby-2.1.5#global/gems/bundler-1.7.6/lib/bundler/runtime.rb:76:in `require'
from /home/kevin/.rvm/gems/ruby-2.1.5#global/gems/bundler-1.7.6/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
from /home/kevin/.rvm/gems/ruby-2.1.5#global/gems/bundler-1.7.6/lib/bundler/runtime.rb:72:in `each'
from /home/kevin/.rvm/gems/ruby-2.1.5#global/gems/bundler-1.7.6/lib/bundler/runtime.rb:72:in `block in require'
from /home/kevin/.rvm/gems/ruby-2.1.5#global/gems/bundler-1.7.6/lib/bundler/runtime.rb:61:in `each'
from /home/kevin/.rvm/gems/ruby-2.1.5#global/gems/bundler-1.7.6/lib/bundler/runtime.rb:61:in `require'
from /home/kevin/.rvm/gems/ruby-2.1.5#global/gems/bundler-1.7.6/lib/bundler.rb:133:in `require'
from /home/kevin/workspace/applications/ems-heroes/config/application.rb:6:in `<top (required)>'
from /home/kevin/.rvm/gems/ruby-2.1.5/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:78:in `require'
from /home/kevin/.rvm/gems/ruby-2.1.5/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:78:in `block in server'
from /home/kevin/.rvm/gems/ruby-2.1.5/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:75:in `tap'
from /home/kevin/.rvm/gems/ruby-2.1.5/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:75:in `server'
from /home/kevin/.rvm/gems/ruby-2.1.5/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from /home/kevin/.rvm/gems/ruby-2.1.5/gems/railties-4.2.0/lib/rails/commands.rb:17:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
I googled around and didnt find much. Any advice is greatly appreciated.
Thanks!
It turned out that my issue was coming from the dependency 'debug_inspector'.
Thanks to this: https://github.com/banister/binding_of_caller/issues/39
I just had to run:
$ gem uninstall debug_inspector
$ bundle install

Cannot load such file -- unicorn/version (LoadError)

Attempting to switch from WEBrick to Unicorn, I've got the Unicorn gem v 4.8.1 installed on my machine [via "gem install unicorn"] and it's also located in my Gemfile ["gem "unicorn", "~> 4.8.1"], for which I've successfully run bundle install.
However, when starting the server locally via "rails s" (worked fine pre-Unicorn), I get the following error:
...../vendor/cache/ruby/1.9.1/gems/unicorn-4.8.1/lib/unicorn/const.rb:44:in `require': cannot load such file -- unicorn/version (LoadError)
from /Users/johndoe/Sites/my_app/vendor/cache/ruby/1.9.1/gems/unicorn-4.8.1/lib/unicorn/const.rb:44:in `<top (required)>'
from /Users/johndoe/Sites/my_app/vendor/cache/ruby/1.9.1/gems/unicorn-4.8.1/lib/unicorn.rb:108:in `require'
from /Users/johndoe/Sites/my_app/vendor/cache/ruby/1.9.1/gems/unicorn-4.8.1/lib/unicorn.rb:108:in `<top (required)>'
from /Users/johndoe/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `require'
from /Users/johndoe/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
from /Users/johndoe/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `each'
from /Users/johndoe/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `block in require'
from /Users/johndoe/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `each'
from /Users/johndoe/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `require'
from /Users/johndoe/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler.rb:132:in `require'
from /Users/johndoe/Sites/my_app/config/application.rb:7:in `<top (required)>'
from /Users/johndoe/Sites/my_app/vendor/cache/ruby/1.9.1/gems/railties-3.2.13/lib/rails/commands.rb:53:in `require'
from /Users/johndoe/Sites/my_app/vendor/cache/ruby/1.9.1/gems/railties-3.2.13/lib/rails/commands.rb:53:in `block in <top (required)>'
from /Users/johndoe/Sites/my_app/vendor/cache/ruby/1.9.1/gems/railties-3.2.13/lib/rails/commands.rb:50:in `tap'
from /Users/johndoe/Sites/my_app/vendor/cache/ruby/1.9.1/gems/railties-3.2.13/lib/rails/commands.rb:50:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
I'm thinking this may be due to using RVM? When I type 'which gem "unicorn"' I get:
/Users/johndoe/.rvm/rubies/ruby-1.9.3-p392/bin/gem
/Users/johndoe/.rvm/gems/ruby-1.9.3-p392/bin/unicorn
Also for reference, my $PATH: /Users/johndoe/.rvm/rubies/ruby-1.9.3-p392/bin/gem:/usr/local/rvm/bin:/Users/joh‌​ndoe/.rvm/gems/ruby-1.9.3-p392/bin:/Users/johndoe/.rvm/gems/ruby-1.9.3-p392#globa‌​l/bin:/Users/johndoe/.rvm/rubies/ruby-1.9.3-p392/bin:/Users/johndoe/.rvm/bin:/usr‌​/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin:/usr/local/git/bin
"bundle show unicorn" gives: /Users/johndoe/Sites/my_app/vendor/cache/ruby/1.9.1/gems/unicorn-4.8.1
The application successfully deploys to Heroku, so I believe this issue is isolated to my machine (rather than being an issue with the application). Any ideas on how to solve this?
I seemed to fix the problem by uninstalling the gem via "sudo bundle exec gem uninstall unicorn", then reinstalling it via standard "sudo bundle install"
Still not sure exactly why the issue occurred, but that fix did seem to work.
Can you used this..
$ rails server unicorn
or
bundle exec unicorn -p 3000
Still not sure what caused this problem.
I solved this simply by reinstalling the unicorn gem.
gem uninstall unicorn
bundle install
bundle update

Secret generation in redmine installation fails with error in mysql2/mysql2

I am trying to install redmine 2.3.x on my Debian vServer. I already managed to build ruby from source and installed gems, rails and the apache passenger module. It should work until that point. I used the turotial at domainfactory: http://www.df.eu/de/service/df-faq/cloudserver/anleitungen/ruby-on-rails-installieren-debian-ubuntu/ .
After that I downloaded and extracted the redmine application as described here: http://www.redmine.org/projects/redmine/wiki/RedmineInstall#Installation-procedure. I created a mysql account and database, made a copy of the config/database.yml.example -> config/database.yml and filled in the correct values.
After that I installed bundler with
gem install bundler
And did go on with preparing the environment:
bundle install --without development test
All these commands did succeed.
After that I wanted to generate the secret token with the fallowing command:
rake generate_secret_token
The execution was interrupted with the fallowing message:
# rake generate_secret_token --trace
rake aborted!
cannot load such file -- mysql2/mysql2
/usr/local/lib/ruby/gems/2.0.0/gems/mysql2-0.3.13/lib/mysql2.rb:8:in `require'
/usr/local/lib/ruby/gems/2.0.0/gems/mysql2-0.3.13/lib/mysql2.rb:8:in `<top (required)>'
/usr/local/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `require'
/usr/local/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
/usr/local/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `each'
/usr/local/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `block in require'
/usr/local/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `each'
/usr/local/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `require'
/usr/local/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler.rb:132:in `require'
/var/www/potato/config/application.rb:7:in `<top (required)>'
/usr/local/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
/usr/local/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
/var/www/potato/Rakefile:5:in `<top (required)>'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/rake_module.rb:25:in `load'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/rake_module.rb:25:in `load_rakefile'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:637:in `raw_load_rakefile'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:94:in `block in load_rakefile'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:165:in `standard_exception_handling'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:93:in `load_rakefile'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:77:in `block in run'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:165:in `standard_exception_handling'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:75:in `run'
/usr/local/lib/ruby/gems/2.0.0/gems/rake-10.1.0/bin/rake:33:in `<top (required)>'
/usr/local/bin/rake:23:in `load'
/usr/local/bin/rake:23:in `<main>'
I was trying to resolve this by checking versions and installed gems.
Ruby: ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-linux]
Rails: Rails 3.2.13
Gems: 1.8.25
Redmine: 2.3.3
I verified with gem list --local that the gem "mysql2" is installed.
gem "mysql": mysql2 (0.3.13)
As the problem seems to rely on this, I tried reinstalling the package, but this did not help.
What did I wrong here?
Thanks in advance,
Sebastian Büttner
I found this error happens if you don't have the following package installed in your system (at least on Debian 9). So run command:
apt-get install default-libmysqlclient-dev
try bundle exec rake generate_secret_token
(if #1 does not help) Check if mysql2 is presented in output list for bundle list (it is different with gem list!). Be careful that redmine install DB adapter according to your settings in database.yml (but I think you install it correctly)
Please, check if you have necessary VC runtime installed. Please, check the VC runtime dll version, your mysql vendor dll is dependent upon.

Why won't Rails' console start or make new apps?

A few days ago I updated my gems because things weren't running so fine, so I went back to 1.4.2. Since then I'm getting all kind of weird errors.
I'm using Ruby 2.0.0p247, Rails 4.0 and Ubuntu.
If I try to start a new app using rails new eraseme, everything goes fine until it's time to do bundle install. The output is:
run bundle install
/usr/local/lib/ruby/gems/2.0.0/gems/railties-4.0.0/lib/rails/generators/app_base.rb:270:in `require': cannot load such file -- bundler (LoadError)
from /usr/local/lib/ruby/gems/2.0.0/gems/railties-4.0.0/lib/rails/generators/app_base.rb:270:in `bundle_command'
from /usr/local/lib/ruby/gems/2.0.0/gems/railties-4.0.0/lib/rails/generators/app_base.rb:277:in `run_bundle'
from (eval):1:in `run_bundle'
from /usr/local/lib/ruby/gems/2.0.0/gems/thor-0.18.1/lib/thor/command.rb:27:in `run'
from /usr/local/lib/ruby/gems/2.0.0/gems/thor-0.18.1/lib/thor/invocation.rb:120:in `invoke_command'
from /usr/local/lib/ruby/gems/2.0.0/gems/thor-0.18.1/lib/thor/invocation.rb:127:in `block in invoke_all'
from /usr/local/lib/ruby/gems/2.0.0/gems/thor-0.18.1/lib/thor/invocation.rb:127:in `each'
from /usr/local/lib/ruby/gems/2.0.0/gems/thor-0.18.1/lib/thor/invocation.rb:127:in `map'
from /usr/local/lib/ruby/gems/2.0.0/gems/thor-0.18.1/lib/thor/invocation.rb:127:in `invoke_all'
from /usr/local/lib/ruby/gems/2.0.0/gems/thor-0.18.1/lib/thor/group.rb:233:in `dispatch'
from /usr/local/lib/ruby/gems/2.0.0/gems/thor-0.18.1/lib/thor/base.rb:439:in `start'
from /usr/local/lib/ruby/gems/2.0.0/gems/railties-4.0.0/lib/rails/commands/application.rb:43:in `<top (required)>'
from /usr/local/lib/ruby/gems/2.0.0/gems/railties-4.0.0/lib/rails/cli.rb:15:in `require'
from /usr/local/lib/ruby/gems/2.0.0/gems/railties-4.0.0/lib/rails/cli.rb:15:in `<top (required)>'
from /usr/local/lib/ruby/gems/2.0.0/gems/railties-4.0.0/bin/rails:9:in `require'
from /usr/local/lib/ruby/gems/2.0.0/gems/railties-4.0.0/bin/rails:9:in `<top (required)>'
from /usr/local/bin/rails:23:in `load'
from /usr/local/bin/rails:23:in `<main>'
If I try to open the console, I get:
>> bundle exec rails console
Loading development environment (Rails 4.0.0)
/usr/local/lib/ruby/2.0.0/irb/locale.rb:150:in `block in search_file': undefined method `try_activate' for Gem:Module (NoMethodError)
from /usr/local/lib/ruby/2.0.0/irb/locale.rb:158:in `block in each_localized_path'
from /usr/local/lib/ruby/2.0.0/irb/locale.rb:167:in `each_sublocale'
from /usr/local/lib/ruby/2.0.0/irb/locale.rb:157:in `each_localized_path'
from /usr/local/lib/ruby/2.0.0/irb/locale.rb:145:in `search_file'
from /usr/local/lib/ruby/2.0.0/irb/locale.rb:124:in `find'
from /usr/local/lib/ruby/2.0.0/irb/locale.rb:108:in `load'
from /usr/local/lib/ruby/2.0.0/irb/locale.rb:32:in `initialize'
from /usr/local/lib/ruby/2.0.0/irb/init.rb:114:in `new'
from /usr/local/lib/ruby/2.0.0/irb/init.rb:114:in `init_config'
from /usr/local/lib/ruby/2.0.0/irb/init.rb:16:in `setup'
from /usr/local/lib/ruby/2.0.0/irb.rb:380:in `start'
from /usr/local/lib/ruby/gems/2.0.0/gems/railties-4.0.0/lib/rails/commands/console.rb:90:in `start'
from /usr/local/lib/ruby/gems/2.0.0/gems/railties-4.0.0/lib/rails/commands/console.rb:9:in `start'
from /usr/local/lib/ruby/gems/2.0.0/gems/railties-4.0.0/lib/rails/commands.rb:64:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
Have you already installed bundler? If not, try:
gem install bundler
If so, try:
gem install bundler --pre
If you running Ruby version manager, what version are you running? You might be set to the wrong version of Ruby.
I think it would be easier for you if you used RVM or some other version manager.
if you have multiple versions of rubygems installed, uninstall all but the one you want to use.
I think rails 4 requires rubygems 2.x.
Also check the bundler version.

problem installing webrick / mogrel or any other server for Rails 3

I have tried various installation methods for deploying a WEBrick and mongrel from the terminal. When I enter the rails server command I get the following:
Toran1$ rails server
/Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/mysql2-0.3.2/lib/mysql2.rb:8:in `require': dlopen(/Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/mysql2-0.3.2/lib/mysql2/mysql2.bundle, 9): Library not loaded: libmysqlclient.18.dylib (LoadError)
Referenced from: /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/mysql2-0.3.2/lib/mysql2/mysql2.bundle
Reason: image not found - /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/mysql2-0.3.2/lib/mysql2/mysql2.bundle
from /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/mysql2-0.3.2/lib/mysql2.rb:8:in `<top (required)>'
from /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/bundler-1.0.13/lib/bundler/runtime.rb:68:in `require'
from /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/bundler-1.0.13/lib/bundler/runtime.rb:68:in `block (2 levels) in require'
from /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/bundler-1.0.13/lib/bundler/runtime.rb:66:in `each'
from /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/bundler-1.0.13/lib/bundler/runtime.rb:66:in `block in require'
from /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/bundler-1.0.13/lib/bundler/runtime.rb:55:in `each'
from /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/bundler-1.0.13/lib/bundler/runtime.rb:55:in `require'
from /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/bundler-1.0.13/lib/bundler.rb:120:in `require'
from /Users/Toran1/Sites/simple_cms/config/application.rb:7:in `<top (required)>'
from /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/railties-3.0.7/lib/rails/commands.rb:28:in `require'
from /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/railties-3.0.7/lib/rails/commands.rb:28:in `block in <top (required)>'
from /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/railties-3.0.7/lib/rails/commands.rb:27:in `tap'
from /Users/Toran1/.rvm/gems/ruby-1.9.2-head/gems/railties-3.0.7/lib/rails/commands.rb:27:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
I have installed the gem both locally and at the root level, and I also have navigated to the application folder before issuing the command. Any help would be appreciated!
Webrick will install automatically if you install rails in a correct manner.
Try this link
Here
And if you don't want to install rails again, try to install server using gem command
Dont forget to include the gems in Gemfile and to run "bundle install"
If you are using Rails < 3.1 you need to use version ~> 0.2.7 of the mysql2 gem
Checkout the documentation and search for active record: https://github.com/brianmario/mysql2
I'm not sure if that will help solve this problem directly, but it may solve others that you may encounter.
Just update your bundler, maybe of any-one of the older gem is conflicting with latest one, this type of issues arises.
gem install bundler
and then bundler install
If you find again error, then delete GEM.lock file, then run
bundler install
This may resolve the issue.

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