Hi I'd like to help with a wiki article, if others think it's necessary. I've spent the better part of the last 3 days trying to have sign in with Facebook and Google for a site. You can see the commit history below.
Because of the mention in the documentation about Multiple Oath Models I ended up down a rabbit hole that I didn't really need to go down, wasting some time. I then struggled mightily with the difference between oauth and oauth2 in my routes and config.
If someone more experienced than myself is willing to look over a tutorial for setting up sign in with facebook and google, and the community thinks it would be helpful, I'd be happy to try to do so.
Also the error
Not found. Authentication passthru, found https://github.com/plataformatec/devise/blob/master/app/controllers/devise/omniauth_callbacks_controller.rb in the passthru method isn't really helpful. I'd be happy to help address that if there is someone who would be willing to look over my work.