docker-compose up fails when the database container is not (yet) started

[maltezacharias]

Describe the bug
When db container is not running the main app container will stop

To Reproduce
Steps to reproduce the behavior:

1. Introduce a config change that will cause the database to fail to come up
2. run docker-compose up or deploy.sh

Error 
 django.db.utils.OperationalError: could not translate host name "database" to address: Name or service not known

Expected behavior
the main app container should wait for the database to become available:

The problem of waiting for a database (for example) to be ready is really just a subset of a much larger problem of distributed systems. In production, your database could become unavailable or move hosts at any time. Your application needs to be resilient to these types of failures.

(Docs on https://docs.docker.com/compose/startup-order/)

Additional context
The script should indicate clearly that it's waiting for the database to come up. In Build environments it should probably timeout after a while?