Gemfile in warden-github-rails-1.0.0 vs Gemfile in warden-github-rails-1.0.1

@@ -4,9 +4,22 @@
 
 if ENV['EDGE']
   gem 'warden-github', :github => 'atmos/warden-github'
 end
 
+rails_version = ENV['RAILS_VERSION']
+
+rails_opts = case rails_version
+             when 'master'
+               { :github => 'rails/rails' }
+             when nil
+               {}
+             else
+               "~> #{rails_version}"
+             end
+
+gem "rails", rails_opts
+
 group :development do
   unless ENV['CI']
     gem 'debugger',   :platforms => :ruby_19, :require => false
     gem 'ruby-debug', :platforms => :ruby_18, :require => false
   end