Allow users to add new rounds from the main page

[geerlingguy]

Add either a separate form, or ability to hit + and add a new row to the existing Overview page.

[geerlingguy]

Well, at this point I have the whole form working (except for adding new items). But being able to save changes (like turning voting on or off) is nice.

[geerlingguy]

Idea for this is to:

• Render the extra (empty) row in the Python template with a class like round-hidden
• Update the save logic in the POST handler to ignore this row data if value_1 is empty
• Add some Javascript on the front end that handles a button click ("Add Round"), and when clicked, hides the button and reveals the row.
• Make sure the round_id is set to new so we can pick it up and INSERT it on the backend

[geerlingguy]

It works: