Provides a thin wrapper around the excellent ruby-openid gem from JanRan. Be sure to install that first:
gem install ruby-openid
To understand what OpenID is about and how it works, it helps to read the documentation for lib/openid/consumer.rb from that gem.
More information and usage/integration instructions are available here. You may also want to take a look at the OpenID 2.0 Specification.
Author: David Heinemeier Hansson
Installation:
ruby script/plugin install http://svn.rubyonrails.org/rails/plugins/open_id_authentication/