Startup fails when reusing the container

[ih84ds]

When restarting an existing container, the entrypoint script attempts to recreate afpuser even if it already exists:

groupadd: group 'afpuser' already exists
adduser: The user `afpuser' already exists.

Also, the netatalk daemon exits immediately upon startup with a cryptic error message. It's possible that this is related to the above error, or it could be a totally separate problem.

netatalk is already running (pid = 1), or the lock file is stale.
exited with code 3

To reproduce, simply stop and start the container a few times. I am running via docker-compose, but I don't think that matters.