- handling our edit form save

Notice we've changed to jquery .on notation. That's because the form
doesn't exist in the DOM at the beginning so no data is attached to it
at first.

using .on we attach to it as it shows up in our DOM
- now we need to capture our post_id

Now we capture the post_id with the data attribute and if it's not empty
we add it to our call on wp_insert_post which allows us to reuse the
same processing function for our form.