So, from a stackato perspective your change makes perfect sense. However, if you look at the code without caring anything about stackato or even knowing what stackato is then it makes more sense to call it `DATABASE_URI`. 

Perhaps the simplest is a hack along these lines:

```
# If you run this through Stackto using PostgreSQL it'l be called
# `POSTGRESQL_URL` instead and for simplicity we make that
# an optional default
SQLALCHEMY_DATABASE_URI = os.environ.get( 
    'DATABASE_URI',
    os.environ.get(
    )
)
```