Configured the Devise initializer with Facebook app keys

config/initializers/devise.rb

@@ -251,4 +251,5 @@ Devise.setup do |config|
   # When using omniauth, Devise cannot automatically set Omniauth path,
   # so you need to do it manually. For the users scope, it would be:
   # config.omniauth_path_prefix = '/my_engine/users/auth'
+  config.omniauth :facebook, "", "ENV['FACEBOOK_SECRET_ID']"
 end