Fix Docker deployment

[mhulet]

Multiple contributors have reported issues with the Docker setup.

[kenorb]

What are the errors?

[mhulet]

WIP https://github.com/extinctionrebellion/RebelsManager/tree/docker-setup

@kenorb I'm starting a setup from scratch. I will comment again when I have details about what is going wrong.

[mhulet]

It now works great locally with updates on the docker-setup branch. I learned a lot about Docker in the process.

Next step: docker-compose.production.yml and making sure it works on our own server.

[mhulet]

I had no time working on this. Anyone fluent with Docker in production? 👋

Our goal is to make sure that any XR Branch can have the Rebels Manager running on their Debian server, and then having documentation to explain how the app can be updated.