Thanks for sharing..
Just to mention that, you could also provide a top level .env file and put the following:
COMPOSE_PROJECT_NAME=whatever
Now you can decouple your project directory structure from what’s docker-compose is using by default..
Also, Since you’re using it within VSCode when you first spin up the devcontainer (open in container) you can perform mix ecto.setup manually (the first time or as many times as needed after some migrations for example). So I’m not sure if it’s necessary to have it in the command section of your compose file.
Also if you have some equivalent for production, don’t hesitate to share them too 
