Add Users to app

The most basic model: User

- [x] Generate User model
- [x] Generate Users controller
  * string: email
  * string: password
  * string: confirmation_hash
  * datetime: confirmed_at
- [ ] Add resource route for user
- [ ] Add actions to controller
- [ ] Create `/users/new` view
- [ ] Create `/users/verify/:confirmation_hash` view

I'm sure there's more stuff to do, I just don't know what it is yet.