What is my POSTGRES_DB variable supposed to be?

So I have created a very, very basic Django app using cookiecutter. It’s not even at the “hello, world!” stage yet. The docker image built successfully as far as I can tell. I chose to set up a Postgres db when I was prompted to during fly launch. Then it never successfully deployed because there were a bunch of unbound environment variables. So I set them using fly secrets set but the one that’s missing and I can’t find anywhere is POSTGRES_DB.

What is it?

Is there some truly beginner friendly guide out there? I feel as though I am in way, way over my head here.

Edit: by the way, a secondary problem, any command I try to run for seeing information about the postgres app fails. So when I try flyctl postgres users list or flyctl postgres db list for instance, it only tells me that some_app is not a postgres app, where some_app is whatever app I was just attempting to deploy. Am I using this command incorrectly?

Edit2: Oh, and is there anyway to prevent Fly from trying to re-deploy every time I change a secret?

You’ll need to first create a separate app for the postgres database.

Then you’ll need to attach the postgres db to the app and then DATABASE_URL will be set in your app.