How to use newer versions of RubyGems with older versions of Rails

adjusted_environment.rb

# IN ENVIRONMENT.RB, ADD THESE LINES AFTER THE BOOT SECTION AND BEFORE THE INITIALIZER BLOCK
# (e.g. on line 13 of most environment.rb's):

if Gem::VERSION >= "1.3.6" 
  module Rails
    class GemDependency
      def requirement
        r = super
        (r == Gem::Requirement.default) ? nil : r
      end
    end
  end
end