Adding tests for the Edit Profile page.
Adding the edit method in User controller.
Adding the edit user template.
Adding settings link in the header and adding tests
Augmenting the valid_signin utility helper function
Adding the initial update function in the User controller.
The update action in the User controller for handling updates with valid information.
Handling authorization in the User controllers. Adding tests for making edit and update actions inaccessible for non-signed-in users.
Requiring the only the user to edit his settings. Adding tests, checks for correct user in User controller and current_user? helper function.
Adding friendly forwarding to users who are not logged in. 

* Adding tests.
* Updating the signed_in_user function in the User controller to store current URL
* Adding helper functions redirect_back_or and store_location
* Adding redirect_back_or call in the Sessions controller to forward to the user to the desired URL
Showing all users only to the signed in user page. 

* Test for showing signin page to if user is not signed in
* Test for listing all the users
* Adding validation that the index page is only shown to signed in user
* Adding the index template for the User controller
Adding CSS for the users index.
Adding link to the users index in the header if the user is signed in.