Create docker-compose.yml

[Kazio73]

For iredmail container on portianer.io

[iredmail]

Missing volume: -v /iredmail/data/mailboxes:/var/vmail/vmail1

[JReming85]

I would suggest mounting the environment files instead of listing them in the compose file for easier maintanace

- '/iredmail/iredmail-docker.conf:/iredmail-docker.conf'
Then you can just call it at the end

        image: 'iredmail/mariadb:stable'
	environment:
               - '/iredmail-docker.conf'