APPS reusable template example app

:koala: :+1:

A new app that shows how to use `this.renderTemplate()` to recycle common elements.

/cc @zendesk/quokka

### References
 - Jira link: 

### Risks
 - None

### Screenshot
![screen shot 2014-09-12 at 1 44 39 pm](https://cloud.githubusercontent.com/assets/5535625/4245137/522167c6-3a2f-11e4-9d44-5145511e78ab.png)
#nitpick can we do `{ username: currentUser }`?