Sync GitLab group to Mattermost team
Description
We support creating a Mattermost team during GitLab group creation, but we don't keep that team's members updated with members of the GitLab group. We should.
Proposal
Links / references
Documentation blurb
(Write the start of the documentation of this feature here, include:
- Why should someone use it; what's the underlying problem.
- What is the solution.
- How does someone use this
During implementation, this can then be copied and used as a starter for the documentation.)