about ruby on rails association

when i use belongs_to association in rails, the the foreign which is automatically generated or i have to add that column first in the schema and then use association

class ClientQuestionnaire < ActiveRecord::Base
  belongs_to :question , :class_name => 'Questionnaire'    
end





class Questionnaire < ActiveRecord::Base

  has_many :client_questionnaires

end

Do i have to make question_id first in client_questionnaires table and then use belongs_to :question , :class_name => 'Questionnaire' statement in my model