added support for .env files

[mnzaki]

This allows users to simply set values in a .env file and keep using the docker-compose.yml file as-is, so that updates are easier

[maltokyo]

Thanks, this would be great! I have a question on this. I have to comment out the port lines for 80 and 443, as my reverse proxy handles that. Any way to do this "comment out" or cancel lines with .env?

[mnzaki]

@maltokyo one way would be to also put those ports in the .env file and change the docker-compose.yml to bind them to whatever is in .env

ports:
  - "${PUBLIC_HTTP_PORT}:80"
  - "${PUBLIC_HTTPS_PORT}:443"

Unfortunately I don't know of anyway to fully remove the port binding

[silviot]

Nice! I had the same thoughts reading the README.

I think this PR should also change this paragraph of the README.

Note that I'm not affiliated with the project.