Fix the docker-compose installation

[aumetra]

Since moving to Dhall, the Docker Compose installation has been broken.
We could probably move the Compose file into a contrib directory and place a Dhall configuration file next to it that pulls some configuration values from environment variables.

[eyduh]

Hiya,
I'm working on a setup using docker-compose. So far I have compiled the binaries using Dockerfiles like the ones in the git and I now have two docker images with binaries in /app but am a bit lost for the next step.

I feel like the way to go would be to have something like a ./config:/app/config bind mount, with the dhall/.env file in it, then another line like command: /app/kitsune --config /app/config/config.dhall in the compose file could make it work?

Gonna spin up a VM and play a bit without docker to get to know kitsune better and work from there.

[aumetra]

@eyduh Thank you for taking a look at this. Really appreciated!

Yeah, I believe something like a mount point for the configuration file might be our best bet here, since we wouldn't have to reinvent the wheel in the sense of having to encode all the configuration options in environment variables.

We should probably also modify the Dockerfile do copy the Dhall types (i.e. the kitsune/config directory with all these different .dhall files) into the resulting image, so users don't have to clone the repository and install the dhall CLI tool to produce a working configuration (that's what you have to do to configure the Shuttle deployment at the moment and I don't think it's really ideal)