Auth0 is now available on Heroku as an add-on (private beta for now), making it incredibly easy to add Enterprise SSO, Consumer Logins, Directories queries, user access audit and many advanced identity management to any app hosted there. See here for a complete list of supported identity providers in Auth0: Consumer and Enterprise.

A 3 min video is worth 1,000,000 words. Take a look:

Try Auth0 yourself!