Google console.developers.google.com Note, please make sure under “APIs” that you have the “Contacts API” and “Google+ API” enabled
Facebook developers.facebook.com/apps/
Twitter apps.twitter.com
LinkedIn www.linkedin.com/secure/developer
GitHub github.com/settings/applications
github.com/plataformatec/devise/wiki/OmniAuth:-Overview www.digitalocean.com/community/tutorials/how-to-configure-devise-and-omniauth-for-your-rails-application sourcey.com/rails-4-omniauth-using-devise-with-twitter-facebook-and-linkedin/