Publish docker image to docker hub

[SheepReaper]

Is your feature request related to a problem? Please describe.
Downloading the source to build the docker image is inconvenient. A ready image in docker hub is ideal.

Describe the solution you'd like
Create a GitHub workflow to push the built shell-craft tag to docker hub

Describe alternatives you've considered
None

Additional context
I want to:

• docker run JohnnyIrvin/shell-craft

[JohnnyIrvin]

I'll be able to work on this when #14 is finished. We have a PR (#46) but it has unexpected behavior.

We want to get the env var from host without passing it into Docker run, but I wasn't able to find anything on that in the docs.