From backend OTP app to Phoenix app

In this episode we migrate StatWatch, a purely back-end OTP app into a new Phoenix 1.3 project in the following phases:

1. Generate the Phoenix app Copy StatWatch into the Phoenix app Make some small improvements
2. Add it and its child worker to the supervision tree
3. Organize the app into Phoenix 1.3 Contexts
4. Hook it up to the DB Set up some basic CRUD

In Part 2, we'll set up login/log out functionality via sessions, store the current user in a plugable auth controller and build out a template to display stats.