Update README.md

[perryzjc]

What this PR does:

This pull request updates the doc based on high level new features we implemented for this semeseter

Include screenshots, videos, etc.

Who authored this PR?

1. Perry (Jingchao) Zhong @perryzjc

How should this PR be tested?

• Is there a deploy we can view?
• What do the specs/features test?
• Are there edge cases to watch out for?

Are there any complications to deploying this?

Checklist:

• Has this been deployed to a staging environment or reviewed by a customer?
• Tag someone for code review (either a coach / team member)
• I have renamed the branch to match PivotTracker's suggested one (necessary for BlueJay) (e.g. michael/12345-add-new-feature Any branch name will do as long as the story ID is there. You can use git checkout -b [new-branch-name])

[ArushC]

Looks good. I assume the mermaid code is just a diagram.