cannot load such file -- script/../config/boot (LoadError) after OSX Mavericks - ruby-on-rails

Question

I was doing development on a ruby on a rails application (v2.3) yesterday and decided to update my iMac to OSX Mavericks. Now, every time I try to run my application locally, I get the following error. Does anyone know whats causing this?
Run like this:
script/server -e development
Error:
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require': cannot load such file -- script/../config/boot (LoadError)
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require'
from script/server:2:in `<main>'
script/server (file)
#!/usr/bin/env ruby
require File.dirname(__FILE__) + '/../config/boot'
require 'commands/server'
It was working fine before installing OSX Mavericks.
Things I Noticed:
the version of ruby installed in now 2.0 (it was v1.8.7 before)
FYI: I'm still fairly new to rails.
After Installing RVM:
Ok so I setup RVM and made sure the version of ruby (1.8.7) and rails (2.3.11) are installed and configured as the default.
Installed RVM:
curl -L https://get.rvm.io | bash -s stable --rails
Install Ruby 1.8.7:
rvm install ruby-1.8.7-p374
Set v1.8.7 as the default version:
rvm --default use 1.8.7
Install Rails v2.3.11:
gem install rails -v 2.3.11
Install all the gems from system
rvm system ; rvm gemset export system.gems ; rvm 1.8.7 ; rvm gemset import system
Now when I run my app, I get the following error: (what am I missing?)
=> Booting WEBrick...
/Users/imaginationplus/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/site_ruby/1.8/rubygems/core_ext/kernel_require.rb:53:in `gem_original_require': no such file to load -- haml (MissingSourceFile)
from /Users/imaginationplus/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/site_ruby/1.8/rubygems/core_ext/kernel_require.rb:53:in `require'
from /Users/imaginationplus/gitlocal/dfc_workshop/vendor/rails/activesupport/lib/active_support/dependencies.rb:510:in `require'
from /Users/imaginationplus/gitlocal/dfc_workshop/vendor/rails/activesupport/lib/active_support/dependencies.rb:355:in `new_constants_in'
from /Users/imaginationplus/gitlocal/dfc_workshop/vendor/rails/activesupport/lib/active_support/dependencies.rb:510:in `require'
from /Users/imaginationplus/gitlocal/dfc_workshop/vendor/plugins/haml/init.rb:5:in `evaluate_init_rb'
from ./script/../config/../vendor/rails/railties/lib/rails/plugin.rb:95:in `evaluate_init_rb'
from /Users/imaginationplus/gitlocal/dfc_workshop/vendor/rails/activesupport/lib/active_support/core_ext/kernel/reporting.rb:11:in `silence_warnings'
from ./script/../config/../vendor/rails/railties/lib/rails/plugin.rb:91:in `evaluate_init_rb'
from ./script/../config/../vendor/rails/railties/lib/rails/plugin.rb:44:in `load'
from ./script/../config/../vendor/rails/railties/lib/rails/plugin/loader.rb:33:in `load_plugins'
from ./script/../config/../vendor/rails/railties/lib/rails/plugin/loader.rb:32:in `each'
from ./script/../config/../vendor/rails/railties/lib/rails/plugin/loader.rb:32:in `load_plugins'
from ./script/../config/../vendor/rails/railties/lib/initializer.rb:292:in `load_plugins'
from ./script/../config/../vendor/rails/railties/lib/initializer.rb:142:in `process'
from ./script/../config/../vendor/rails/railties/lib/initializer.rb:97:in `send'
from ./script/../config/../vendor/rails/railties/lib/initializer.rb:97:in `run'
from /Users/imaginationplus/gitlocal/dfc_workshop/config/environment.rb:14
from /Users/imaginationplus/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/site_ruby/1.8/rubygems/core_ext/kernel_require.rb:53:in `gem_original_require'
from /Users/imaginationplus/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/site_ruby/1.8/rubygems/core_ext/kernel_require.rb:53:in `require'
from /Users/imaginationplus/gitlocal/dfc_workshop/vendor/rails/activesupport/lib/active_support/dependencies.rb:510:in `require'
from /Users/imaginationplus/gitlocal/dfc_workshop/vendor/rails/activesupport/lib/active_support/dependencies.rb:355:in `new_constants_in'
from /Users/imaginationplus/gitlocal/dfc_workshop/vendor/rails/activesupport/lib/active_support/dependencies.rb:510:in `require'
from /Users/imaginationplus/gitlocal/dfc_workshop/vendor/rails/railties/lib/commands/servers/webrick.rb:59
from /Users/imaginationplus/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/site_ruby/1.8/rubygems/core_ext/kernel_require.rb:53:in `gem_original_require'
from /Users/imaginationplus/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/site_ruby/1.8/rubygems/core_ext/kernel_require.rb:53:in `require'
from /Users/imaginationplus/gitlocal/dfc_workshop/vendor/rails/activesupport/lib/active_support/dependencies.rb:510:in `require'
from /Users/imaginationplus/gitlocal/dfc_workshop/vendor/rails/activesupport/lib/active_support/dependencies.rb:355:in `new_constants_in'
from /Users/imaginationplus/gitlocal/dfc_workshop/vendor/rails/activesupport/lib/active_support/dependencies.rb:510:in `require'
from /Users/imaginationplus/gitlocal/dfc_workshop/vendor/rails/railties/lib/commands/server.rb:39
from script/server:3:in `require'
from script/server:3

Answer 1

The main thing to understand from this issue is that you cannot rely on the OS for your ruby version or the gems that you are using within a ruby project. As you create additional ruby apps you may run into trouble with this again.
- To manage the gems use Bundler
Bundler maintains a consistent environment for each ruby applications.
- To manage the Ruby versions use rbenv or rvm

Answer 2

the version of ruby installed in now 2.0 (it was v1.8.7 before)
In 2.x version of Ruby, the current directory is no longer in $LOAD_PATH by default. That means that using require to load files relative to the current directory (such as script/../config/boot which expands to simply config/boot) won't work.
Alternatives are:
edit $LOAD_PATH to include the current directory by e.g. $LOAD_PATH << "."
use require_relative
Above solution was found here