This project is no longer under active development. You are probably looking for Signonotron2.
An OAuth 2-based Single sign-on provider.
This is a rails app with two key rake tasks:
rake clients:create name=ClientName
This will generate an ID and a Secret that can then be used in the app
rake users:create name=Name email@example.com (github=username twitter=username)
This will create the user and send them an email to set their password