Automatic docker deployment with Github Actions

[rk1a]

This addresses #13.
In order for the workflow to go through we need to set up the following secrets in the repository settings:
DOCKERHUB_USERNAME: rk1a
DOCKERHUB_TOKEN: dckr_pat_1rWO2yOF3YQ5BeoZtsUKQfACye4
(we can of course also use a different docker hub account)

I think setting up secrets can only be done by the owner @lauritowal

[lauritowal]

I'll have a look.

@rk1a the image would not be available for the public audience, right? Also is it free to build images via GitHub and upload them to docker hub? Did you try it on another repo?
Could you also please update the project's Readme: What needs to be done after changes to the Image / Dockerfile to start the deployment process? Is pushing to the repo enough? Please describe it a bit there

[rk1a]

• I tried in another repo and it worked there
• But the image would be public on Dockerhub, so I am not sure if that works for us.
• Building and uploading to Dockerhub is free.
• The build is triggered on pushing to the main branch, but probably would be enough if one of the dependency files/Dockerfile itself changes

[rk1a]

This is not needed anymore.