Why does the database end up in /app/data in the "production-compose" Docker example

[luator]

This is just a question for understanding.

I have an application that uses a sqlite database. In rxconfig.py, I have set db_url="sqlite:///reflex.db". When I run reflex run in the root folder of my application, the reflex.db is created in that folder. So far so good.

However, in the "production-compose" Docker example, a "db-data" volume is mounted in /app/data (with the application being in /app). When I run the containers (docker compose up), the database magically get's created in /app/data instead of /app. Why is this the case? I couldn't find anything in the Dockerfile, that would explain this. I also couldn't find anything in the documentation but that might just be because I don't know what to search for.

[luator]

Never mind, I just saw that DB_URL is set in the compose.yaml (I only looked in the Dockerfile before).