Add Fig config

[clue]

http://orchardup.github.io/fig/

[khena]

Very old issue, but I only see it now, because I just use your image to re-install quickly ttrss.

That's my v2 docker-compose.yml file, with proxy network enabled (like traefik or nginx) and a little smtp server. Production ready ! -> https://gist.github.com/khena/57ebd966729470ebfe91f7b71ddf4552

and the env file -> https://gist.github.com/khena/0710441593ecffba550a7ff66605b638