Support for Podman

[sbyount]

Hello, I'm trying to get the app running in Podman. It seems that the Postgres volume cannot be mounted on a Mac with Podman.
Any help appreciated. containers/podman-compose#509

":z is required to use bind volumes for PostgreSQL because of docker-library/postgres#116. This means that currently, it is impossible to use Mac + Podman (Rootless) + PostgreSQL (with bind volume). This is a bit sad situation, it seems like a very common usecase. Hope it changes sometime."