Update the README

[bryantran24]

Here are what the other shubble apps are doing, and like add a picture or 2:

https://github.com/wtg/shubble/blob/main/README.md
https://github.com/wtg/Shuttle-Tracker-SwiftUI/blob/main/README.md

[evanofficial]

want to take a shot at fleshing this out