Environment variables

[codeguru42]

Set environment variables in docker image from GitHub Actions.

[codeguru42]

I'm not sure what I was originally thinking when I created this issue. I'm guessing that I was thinking to set environment variables in the docker image during the build. However, currently I think it would be better to set environment variables during deployment instead. I'm unsure if this needs a separate ticket or should be part of #42. I'll keep it open for now until I decide I should close it.