Add ability to save new updates from frontend

- Fixes #71 

* HOWEVER: After it saves the update, it doesn't do anything with the view. I figured this was a good stopping point, and I'll leave it up to @drewrwilson to determine if we want to fix that before pulling this in.
* NOTE: (also) that this pull request should be merged only after #73 since it builds off commits in that branch, and it'll be easier to see the unique aspects of this change once that PR is merged.

Key ideas:
* use `$('form').serializeObject()` to convert a form into an object full of attributes which can be passed into the `Update()` constructor
* create an event for `submit` which calls a `submit()` function.
* `submit()` prevents the default behavior for the form (which was posting to localhost on my dev machine) and instead creates and saves a new update.