Is there a Docker install guide? First-time setup keeps failing.

That's almost always a startup-order issue — the app container is trying to connect before the database container is actually ready to accept connections yet, especially on a first run where the DB image also needs to initialize. Does your docker-compose.yml have a depends_on with a healthcheck condition on the db service, or just a plain depends_on? A plain one only waits for the container to start, not for the database itself to be ready inside it.

Glad that sorted it — that's a common enough gotcha that we should probably add the healthcheck to our example compose file by default. Thanks for flagging it.