Rails 2.3.5 and bundler

Readme

Remove the config.gem lines from config/environment.rb , we don't need them anymore we are running bundler!
Adjust config/boot.rb, adjust/add config/preinitializer.rb , configure your Gemfile.

Type in console:
bundle install
bundle lock

And your done!

boot.rb

#Make sure Rails.boot! is after this block of code!

class Rails::Boot
  def run
    load_initializer
    extend_environment
    Rails::Initializer.run(:set_load_path)
  end
 
  def extend_environment
    Rails::Initializer.class_eval do
      old_load = instance_method(:load_environment)
      define_method(:load_environment) do
        Bundler.require :default, Rails.env
        old_load.bind(self).call
      end
    end
  end
end

# All that for this:
Rails.boot!

Gemfile

#Example gemfile

source :gemcutter

# Rails 2.3.5
gem 'rails',      '~> 2.3.5', :require => nil
gem 'ruby-mysql', '>= 2.9.1', :require => 'mysql'

gem 'haml',                '2.2.19',  :require => nil
gem 'inherited_resources', '= 1.0.3'
gem 'formtastic',          '>= 0.9.7'
gem 'searchlogic',         '>= 2.4.11'
gem 'will_paginate',       '>= 2.3.12'
gem 'block_helpers',       '>= 0.3.2'

group :cucumber do
  gem 'nokogiri',         '>= 1.4.1', :require => nil
  gem 'webrat',           '>= 0.7.0', :require => nil
  gem 'mongrel',          '>= 1.1.5', :require => nil
  gem 'cucumber-rails',   '>=0.2.4',  :require => nil
  gem 'database_cleaner', '>=0.4.3',  :require => nil
  gem 'selenium-client',  '1.2.18',   :require => nil
  gem 'Selenium',         '1.1.14',   :require => nil
  gem 'rspec',            '>=1.3.0',  :require => nil
  gem 'rspec-rails',      '>=1.3.2',  :require => nil
  gem 'factory_girl',     '>=1.2.3',  :require => nil
  gem 'pickle',           '>=0.2.1',  :require => nil
end

group :test do
  gem 'rspec-rails',             '>= 1.3.2',  :require => nil
  gem 'factory_girl',            '>= 1.2.3',  :require => nil
  gem 'mocha',                   '>= 0.9.8',  :require => nil
  gem 'remarkable_activerecord', '>= 3.1.12', :require => nil
  gem 'remarkable_rails',        '>= 3.1.12', :require => nil
  gem 'faker',                   '>= 0.3.1',  :require => nil  
end

preinitializer.rb

# this code goes in config/preinitializer.rb, which you should create if it doesn't exist
 
begin
  # Require the preresolved locked set of gems.
  require File.expand_path('../../.bundle/environment', __FILE__)
rescue LoadError
  # Fallback on doing the resolve at runtime.
  require "rubygems"
  require "bundler"
  Bundler.setup
end