Generate User model
Create schema.rb
(lesson 6) add validations to User model
Generate migration for adding an index on email
(lesson 6) add index
Migrate database
(lesson 6) convert email to downcase on save
(lesson 6) add bcrypt-ruby to Gemfile
Modify Gemfile.lock
Generate migration for adding password digest
Migrate DB
(lesson 6) Add has_secure_password
(lesson 6) validate password length