Looking for logging into the Ruby Facebook site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Ruby Facebook site. After that you can login as usual with your login credentials.
https://qiita.com/memetics/items/214babcebae32c52933c
https://qiita.com/RYOSUKE310/items/2f9ec73aaecd4d80f997
https://teratail.com/questions/32337
https://teratail.com/questions/76829
https://teratail.com/questions/98890
https://teratail.com/questions/28195
https://medium.com/@chinnatiptaemkaeo/integrate-omniauth-facebook-to-rails-5-1389d760d92a
https://scotch.io/tutorials/integrating-social-login-in-a-ruby-on-rails-application
https://stackoverflow.com/questions/10732701/facebook-login-with-ruby-on-rails
https://code.i-harness.com/ja-jp/q/266c7ef
https://richonrails.com/articles/facebook-authentication-in-ruby-on-rails
https://github.com/facebook/facebook-ruby-business-sdk
https://coderwall.com/p/bsfitw/ruby-on-rails-4-authentication-with-facebook-and-omniauth