GitLab forum error 500

I tried to update the GitLab forum via the web UI, but there was an activerecord error in the console, unfortunately I didn't copy it. The forum now produces a 500 error https://forum.gitlab.com/ :/

Maybe an image rebuild will help.

Runbook: https://gitlab.com/gitlab-com/runbooks/blob/master/howto/discourse-forum.md.