Revert model changes

1. Reverted to commit which contained app/login, app/register routes: https://github.com/lingerio/web_app/commit/895a54f48db9a22c6391f194eb9739f6625b4aed

2. Re-integrated models.

3. Changed references to models.py & untracked models.py

4. minor clean-ups in app.py