Implement refresh functionality

Test Cases:

1. Added a bunch of items without saving, previously would have to manually refresh page to clear them -- refresh functionality allows them to clear.

2. Filter items by a search term, refresh button renders back the full list of items saved to the database. 
this is unreliable if the elements in the DOM ever change.

Marionette has a ui hash that we can set up like this:

```
ui:
  $searchBar: ".search-bar-close"
```

and then we can access it like
`@ui.$searchBar`