As far as I can see from the docker-entrypoint.sh it checks for the presence of database only on the first container start.

I suggest performing this check on every start.

I see some possible scenarios:

1. Database was dropped for cleanup, we'd expect it to be just re-created
2. Database name was changed via ${POSTGRES_DB}, so we'd expect the new database to be created

So In both cases, we just should check if the database already exists and if not then create a new one.

I'm not good at shell programming, not sure if I can make a PR :)