support : SAML toolkit for Ruby on Rails
http://support.onelogin.com/entries/165434-saml-toolkit-for-ruby-on-rails
"Security Assertion Markup Language (SAML) is a standard for logging users into applications based on their session in another context. This has significant advantages over logging in using a username/password: no need to type in credentials, no need to remember and renew password, no weak passwords etc."