Switch from /assets to /public

To allow for future minification, use the real path in the require
declarations rather than express' dynamic /assets.
Use the accounting library to format prices

Include the accounting.js library to format the prices in the UI.
Because it's an unnamed module, we must specifically pass it to the
template when rendering so it has it in scope.
Create an add tracked items page

Create a page that will allow a user to add a tracked item.  Once they
enter in the URI, clicking "populate" should fill in the name,
category, and current price.  Once that is shown, the user will be able
to submit the item to the tracked items list.  (This is yet to be
implemented.)