I've read a lot about Omniauth and OAuth2, and how Omniauth uses OAuth, but I don't really understand what is the aim for each one.
For example, I know that with Omniauth I can get back sent params with
@auth['omniauth.params']
but if I'm using OAuth, without Omniauth, can I do the same?
My real problem is that I don't understand the difference between them, where Omniauth ends and OAuth starts, and what can I do with Omniauth that is not possible with OAuth.