Add readme

Status: **Opened for visibility**
Reviewers: @ry5n @jeffkamo 

## Changes
- Added a readme

## Notes
- Not sure if we really need as much detail about the variables file as I've added here. Might be worth dropping that section. Let me know your thoughts.
- Fixes #3 

Also, I don't like the wording of "Likely a background for an element". Doesn't sound very clear what is meant.

Perhaps "Likely elements that are backgrounds" or "Likely just elements that should exist only in the background."