Add Authentications controller and Authentication model. Remove email from User
-Create login page for new users
-New users save email and password
-User information is saved during first purchase
First pass at new user login form. Authentications view.
Modify to accept only email for new authentication.
-Modify Authentication controller to accept email, email confirmation
-Modify Authenticaiton controller to generate authentication code with 4 hour expiry
-Modify Authentication model - add code and expires_at fields
-Modify view to accept email and email confirmation only