Self hosted gitlab

[matfiz]

I am more than happy to see the support for Gitlab authentication!

It would be useful to add an extra param host_name to allow for custom self-hosted Gitlab domain (instead of the default gitlab.com).

[magikstm]

I'm pretty sure @smancke may be open to a PR adding this feature.

In the meantime, if you self-compile loginsrv and/or caddy + loginsrv, you could try adjusting these 3 lines and I believe it may work:
https://github.com/tarent/loginsrv/blob/master/oauth2/gitlab.go#L13
https://github.com/tarent/loginsrv/blob/master/oauth2/gitlab.go#L33
https://github.com/tarent/loginsrv/blob/master/oauth2/gitlab.go#L34

I don't use Gitlab, so can't test or confirm.

[matfiz]

Thanks a lor @magikstm for your input! This is exactly what I've done locally (caddy+loginsrv) and it works as a charm! I'm have very little experience with golang though and would prefer a real wizzard like @smancke to perform the customization.

[xadereq]

@smancke could you provide this feature soon? Since new version of caddy(1.0.0) its getting harder and harder to use own fork of loginsrv.
It shouldn't be that much time consuming...