OmniAuth
OmniAuth is a flexible authentication system utilizing Rack middleware
OmniAuth is a library that standardizes multi-provider authentication for web applications. It was created to be powerful, flexible, and do as little as possible. Any developer can create strategies for OmniAuth that can authenticate users via disparate systems. OmniAuth strategies have been created for everything from Facebook to LDAP. In order to use OmniAuth in your applications, you will need to leverage one or more strategies. These strategies are generally released individually...