Will you add a GitLab sign in option? And, more importantly, would I be able to have GitLab and GitHub users under the same forum account?
Currently as far as I can tell gitlab auth is a plugin and not part of core Discourse. We don’t really have filesystem access to install plugins, but if it gets integrated upstream then it’s just a matter of enabling it.
I would assume that it’s like other auth methods (if you use the same email address for both it will associate it with the same account).