Initial take for generic issue fields

Created by: tkluck

I'm exploring the possibility for the math project Sage to use gitlab as soon as it migrates to git.

One feature that is currently missing (and that would be a dealbreaker, probably) is the fact that gitlab doesn't allow extra fields for issues. The current trac server allows the reporter to classify issues by severity (enhancement/minor/major/blocker) or by component (algebra/calculus/packages/etc).

I've tried to make a start implementing this, but before polishing I'm interested to know whether you would be willing to merge such a feature upstream.

I'd love to hear your feedback! Timo