added note about Devise
Added note about the authentication gem used in GitLab
Because of question in https://groups.google.com/forum/#!topic/gitlabhq/G2rToah19-Q
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Added note about the authentication gem used in GitLab
Because of question in https://groups.google.com/forum/#!topic/gitlabhq/G2rToah19-Q