Completes chapter 6 exercises.
Completes chapter 7 up to section 7.1.4.
Completes chapter 7 up to section 7.3.
Finishes user sign up. Completes up to Section 7.4.4.
Adds forced SSL for production environment.
Completes exercise 7.6.1. Adds image size option to gravatar.
Completes exercise 7.6.2. Adds tests to confirm errors are displayed after invalid new user submission.
Completes exercise 7.6.3. Removes password digest error message because it's nerdy.
Completes exercise 7.6.4.
Completes exercise 7.6.5.