Finished Ch 6 Tutorial: User Model (pure backend)
Created the User model
-consists of a users table
-lots of regex for email format validation
-Added validation for email uniqueness
-ADDED INDEX to email db column in Ssers table
  $ rails generate migration add_index_to_users_email

 Then editing? a autogenerated .rb file and finally running:
  $ bundle exec rake db:migrate

-Included secure passwords
 added has_secure_password function
 AND generated a field in User db table called password_digest to hold hash via:
 $ rails generate migration add_password_digest_to_users password_digest:string

 and then:
 $ bundle exec rake db:migrate
 $ bundle exec rake test:prepare # for spec

 -ALSO lots of RSpec