Explain funny trick

app/controllers/omniauth_callbacks_controller.rb

@@ -79,6 +79,11 @@ class OmniauthCallbacksController < Devise::OmniauthCallbacksController
   end
 
   def kerberos_spnego
+    # The internal kerberos_spnego provider is a replacement for
+    # omniauth-kerberos. Here we re-use the 'kerberos' provider name to ease
+    # the transition. In time (in GitLab 9.0?) we should remove the
+    # omniauth-kerberos gem and rename the internal 'kerberos_spnego'
+    # provider to plain 'kerberos' and remove this special method.
     oauth['provider'] = 'kerberos'
     handle_omniauth
   end