Scope with joins to get data in Rails 3

Question

Coming from Rails 2 to Rails 3 I\'ve never worked so hard to understand something (side editorial).

Anyway, In a Rails 3 app i have the following models...

User:

Answer 1

Rails 4

Question.joins(Answer.user_answers)

[ http://guides.rubyonrails.org/active_record_querying.html#joining-tables ]