Automatically build and push docker images

[rk1a]

It would be helpful for me if we can auto-build images and push them to dockerhub whenever we change the setup since it takes a long time for me to do this locally.
This seems to be an easy task using Github actions. E.g. there is this tool that sounds like it is exactly what I need: https://github.com/marketplace/actions/build-and-push-docker-images?version=v3.1.1