Update psql.py to deal with multiple apps.
Update psql.py to deal with multiple apps.

Run `./psql.py` to connect with app 'hellolily'.
Provide an app name as the first argument to change the app, i.e. `./psql.py staging`.

HelloLily/hellolily,HelloLily/hellolily,HelloLily/hellolily,HelloLily/hellolily