enable therubyracer
Scaffold user

rails generate scaffold User name:string username:string email:string
rol:string
Model question

rails generate model Question title:string body:text user:references +
user has_many: questions
Model answer

rails generate model Answer body:text user:references
question:references best:boolean + user, question has_many: answers
Model comment

rails generate model Comment body:text question:references
answer:references user:references + question, answer, user has_many
:comments
Model vote

rails generate model Vote answer:references user:references
positive:boolean + user, answer has_many :votes
Model label

rails generate model Label name:string
rails generate model QuestionLabel label:references question:references
+ question, label has_many :question_labels
install devise
added pristine home#index
rake db:migrate
enable devise

rails generate devise User && rake db:migrate