Auth0 is an authentication broker that supports social identity
providers as well as enterprise identity providers such as Active
Directory, LDAP, Google Apps, Salesforce. 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.
omniauth-auth0 is the omniauth strategy for Auth0.

WWW: https://github.com/auth0/omniauth-auth0