consider switching back to omniauth_ldap after merging our patches
omniauth_ldap has become active again https://github.com/intridea/omniauth-ldap/issues/61#issuecomment-181526838
It would be a good idea to check if all gitlab-omniauth_ldap patches are send upstream and if not send new merge requests. Once all patches are merged, we can switch to using omniauth_ldap to avoid maintaining a fork.