Add background attribute (with formatting)

[objarni]

Checklist Ensure all of these are completed before opening the PR:

• [ ] Run goimports
• [ ] Read the contribution guide
• [ ] Read the code of conduct
• [ ] Read the coding standards
• [ ] Tests run with -race
• [ ] Tests written to cover any new code
• [ ] Added yourself to the contributors file

Describe the changes Brief explanation about what changed in this PR.

Closing issues Resolves #

[objarni]

Thanks for merge! Finally my badge is green again - this was one of the blockers (and a badly written unit test which I'm now ignoring!)

This is the repo of the game in case you are interested (very much w.i.p): https://github.com/objarni/rescue-on-fractal-bun