Created a User model
User model validations
Added a stub User show page
Added protected_attributes to use an old sintax: 'attr_acessor''
Merge branch 'gem_protected_atributes' into modeling-users
Added password and encrypted_password attributes to the User model
Finished the password machinery
Added a user factory and tests for show page
Improved the user show page and added a Gravatar
Added a sidebar and some styling