Added foreign key to users on task model.
Added API for users and integrated with tasks into a unified API. Made appropriate changes to URLs.
Combined task manager test case with task model test cases.
Properly set up user authorization on tasks API.
Added CSRF handling to Backbone syncing.
Added mixins for requiring logins and turning off caching for views that require logins.
Integrated login required and cache control mixins into task index view.
Fixed registration form to properly set password.