Discourse piensa que está actualizando, pero no lo está

So, interestingly, it didn’t work until I tried to rebuild the app again. This is what that looked like:

clayh@machine:~$ cd /var/discourse
clayh@machine:/var/discourse$ git pull
remote: Counting objects: 5, done.
remote: Compressing objects: 100% (4/4), done.
remote: Total 5 (delta 0), reused 0 (delta 0), pack-reused 0
Unpacking objects: 100% (5/5), done.
From https://github.com/discourse/discourse_docker
   0b73fae..9b102d5  master     -> origin/master
Updating 0b73fae..9b102d5
Fast-forward
 image/discourse_test/Dockerfile | 2 ++
 1 file changed, 2 insertions(+)
clayh@machine:/var/discourse$ ./launcher app rebuild
Config file was not found, ensure containers/rebuild.yml exists

Available configs ( app )
clayh@machine:/var/discourse$ 

Following that, I hit the Reset Upgrade button and it upgraded as expected and all looks normal. Weird.