Starter Tabs - Adding modules and getting blank

I created a simple tabs starter and began adding controllers and so forth. Once I do, the app turns blank (white screen).

Example in app.js

angular.module('starter', ['ionic', 'starter.controllers', 'starter.services', 'starter.directives'])

I added the starter.filters then in directves.js at the top I have:

 angular.module('starter.directives', [])

That's followed by some directive code. Any reason why this is happening?