Add another container to docker-compose.yaml?

Hi, how do I change docker-compose.yaml to launch another docker container when I run “astro dev start”?

I tried adding this to my docker-compose.override.yaml, but it had no effect

    image: selenium/standalone-chrome
      - "4444:4444"
      - my_project_airflow

I thought it might add that extra container based on the image selenium/standalone-chrome, but it does not. right now I am running just 2 commands every time

astro dev start
docker run -d -p 4444:4444 --network my_project_airflow selenium/standalone-chrome

but would like to understand astro more deeply, so if there is a better solution, please let me know

I think you need just another line, but you about had it
reference: Run your Astro project in a local Airflow environment with the CLI | Astronomer Documentation

version: "3.1"