Docker-compose fails to copy settings.py.in correctly

[jisantuc]

For ./scripts/update, docker-compose insists that it has rebuilt containers, but it doesn't use the new container for some reason. We ran into this with the cp publicmapping/settings.py.in publicmapping/settings.py command. For some reason, settings.py remained unavailable in the django service.

The manual fix (copy outside the container, then build) isn't difficult, but it shouldn't be necessary.