Add jquery-ui to the project.

This is step 1 of 3 (maybe 4) for adding autocomplete to our
  entries form.
This adds jquery-ui using a gem, which helps us stay up to date
  with this javascript library.  I.e., we can update the gem with
  bundle update jquery-ui-rails and get the latest javascript
  for jquery-ui.
We also added a line in app/assets/javascript/application.js that
  tells the asset pipeline that we'd like to include the jquery-ui
  javascript on our pages.
Add an ItemController.

This is primarily for our autocomplete feature.  We needed a service
  that could provide all of the items in the database, not just
  the ones that are already associated to a particular list.
This is step 2 of 3 (maybe 4) for setting up the autocomplete.
Add autocomplete to Item selection.

This is step 3 of 4 (decided on 4 instead of 3).
Uses ItemSerializer to provide a value and label on the item.
Uses jquery-ui's autocomplete.
Uses the base jquery-ui styles, plus adds plenty of our own.
Changes the whole app to send json without any root object.
Fix the find or create logic on entry items.

This is step 4 of 4.
Uses the ActiveRecord autosave: true option, which calls
  autosave_associated_records_for_item.  That method looks for
  an item of the same name and uses that if found.