Add first pass at Ember guidelines

These are the first few things I've seen that are consistently useful. All feedback and input is appreciated.

cc: @jsteiner @BlakeWilliams @seanpdoyle @halogenandtoast @creuter @MattMSumner @JoelQ 
Separation of concerns. I see the controller as the place to handle the things that are directly on the template right now and the route is where I make api calls.

I can see that there are times this rule should be broken but I think some standard of where to put things when would be nice and this is a starting point.