Devise for login

Installed the gem called 'Devise' with 'Simple Form' that generates a User model with additional fields of first_name, last_name, and phone_number. In addition, added presence validations for first_name, last_name, phone_number with a regex format for phone_number. Addtionally, added additional text boxes to their views that allows users to sign up and edit their information.
This is nitpicking, but try to reduce the unnecessary changes to files when commiting with git.