Article
+ picture_size()
User
+ digest(String: string)+ new_token()+ remember()+ forget()+authenticated?(String: token)- downcase_email()- has_secure_password?()
ActiveRecord::Base
+ has_many()+ attr_accessor()+ before_save()+ before_create()+ belongs_to()+ default_scope()+ validates()+ find_by()+ all()+ first()
Group
