Scroll monitor setup

Let's use scroll monitor in our project now. Unfortunately scroll monitor is not a Vue.js plugin, it's just a regular JavaScript library, so it doesn't integrate as nicely as what Vue Resource does.

But that's okay, because it will give us the opportunity to learn some interesting things about how Vue works!

Anyway, we now have a a global object scrollMonitor which has a method create which creates a listener on an element in the page.