Problem with "open_id_authentication" plugin

I just install the plugin.

I didn’t do anything first ( should I? ).

And try “rails server”

And this is what I got (error part):

C:/Ruby192/lib/ruby/gems/1.9.1/gems/activesupport-3.0.6/lib/active_support/dependencies.rb:239:in require': no such file to load -- openid (LoadError) from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activesupport-3.0.6/lib/active_support/dependencies.rb:239:in block in require’ from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activesupport-3.0.6/lib/active_support/dependencies.rb:225:in block in load_dependency' from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activesupport-3.0.6/lib/active_support/dependencies.rb:596:in new_constants_in’ from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activesupport-3.0.6/lib/active_support/dependencies.rb:225:in load_dependency' from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activesupport-3.0.6/lib/active_support/dependencies.rb:239:in require’ from D:/cfecardgame/vendor/plugins/open_id_authentication/lib/open_id_authentication.rb:2:in <top (required)>' from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activesupport-3.0.6/lib/active_support/dependencies.rb:239:in require’ from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activesupport-3.0.6/lib/active_support/dependencies.rb:239:in block in require' from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activesupport-3.0.6/lib/active_support/dependencies.rb:225:in block in load_dependency’ from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activesupport-3.0.6/lib/active_support/dependencies.rb:596:in new_constants_in' from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activesupport-3.0.6/lib/active_support/dependencies.rb:225:in load_dependency’ from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activesupport-3.0.6/lib/active_support/dependencies.rb:239:in require' from D:/cfecardgame/vendor/plugins/open_id_authentication/init.rb:5:in block in class:Plugin’ from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.0.6/lib/rails/plugin.rb:81:in eval' from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.0.6/lib/rails/plugin.rb:81:in block in class:Plugin’ from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.0.6/lib/rails/initializable.rb:25:in instance_exec' from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.0.6/lib/rails/initializable.rb:25:in run’ from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.0.6/lib/rails/initializable.rb:50:in block in run_initializers' from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.0.6/lib/rails/initializable.rb:49:in each’ from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.0.6/lib/rails/initializable.rb:49:in run_initializers' from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.0.6/lib/rails/application.rb:134:in initialize!’ from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.0.6/lib/rails/application.rb:77:in method_missing' from D:/cfecardgame/config/environment.rb:5:in <top (required)>’ from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.0.6/lib/rails/application.rb:103:in require' from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.0.6/lib/rails/application.rb:103:in require_environment!’ from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.0.6/lib/rails/commands.rb:22:in <top (required)>' from script/rails:6:in require’ from script/rails:6:in `’

problem solved by adding two line in gemfile:

gem ‘ruby-openid’ gem ‘rack-openid’

sorry for asking the stupid question…