[FE] Allow restricting group members by a domain whitelist

frontend for https://gitlab.com/gitlab-org/gitlab-ee/issues/7297

Taken from https://gitlab.com/gitlab-org/gitlab-ee/issues/7297#note_161903349

For the UX, I think we can add this under the Permissions, LFS and 2FA section settings in Group general settings.

We can add a new text input with the following attributes:

  • Title: Restrict membership by email
  • Placeholder: e.g. *@ gitlab.com (space added to avoid pinging the company)
  • Help text: Only users with an email address in this domain can be added to the group.

settings

When adding members to the group via email, I think we can validate addresses in the Frontend:

Right domain Wrong domain
invite-email-right invite-email-wrong

If the address didn't belong to the right domain, the option would be greyed out and an warning line would be added:

Only email addresses in the “*@ gitlab.com” domain can be invited to this group

Edited by Luke Bennett