Authenticate to a Rails app that uses Devise + Omniauth provider from an hybrid app

[Daniel Olivares Díaz de León]

Note: This has also been posted at http://stackoverflow.com/questions/36410150/authenticate-to-a-rails-app-that-uses-devise-omniauth-provider-from-an-hybrid

I am building a Rails 4 app that uses Devise for authentication. I have already followed the steps ofhttps://github.com/plataformatec/devise/wiki/OmniAuth:-Overview to add a provider. This works as expected.

An hybrid app (Ionic) will be created for this application as well, however, authentication will be required since the resources will be user-specific. How can I add a "Sign in with [provider]" button on my mobile app that signs in / signs up to my web app using the selected provider? I'm guessing I need token authentication of some sort but I'm confused as what the steps would need to be performed.