Line endings need to be forced to Linux

The scripts that run inside the container need to have Linux line endings. I've fixed this on the pet containers; it looks like we need to do that here too.

This is from Windows 10 Pro with Git for Windows:

```
db_development_1   | /docker-entrypoint-initdb.d/1make-dbusers.sh: line 2: $'\r': command not found
backend-examplar-2018_db_development_1 exited with code 127
```