This service runs as a Google Managed VM.
Deploy with ./deploy.bash.
Then use the Cloud Console to set the new version as the default,
and delete the old instance (lest it keep running):
https://cloud.google.com/console/appengine/versions?project=symbolic-datum-552&moduleId=pushback
Command pushback is a service that monitors a set of GitHub repositories
for incoming Pull Requests, replies with contribution instructions, and
closes the request. This is for projects that don't use Pull Requests.