Publish docker image to container registry

[obbardc]

Should publish a docker container to ghcr.io or dockerhub using GitHub actions.

[juriansluiman]

Yeah I'm kinda new to this type of development, but this should be pushed as an app to some sort of registry 👍

[obbardc]

this is the main thing blocking me from deploying groceri.es, if you enable these in GitHub in preparation i will try to spare some time for an initial implementation:

• GitHub container registry
• GitHub actions

[obbardc]

Fixed in #24