class Vote < ActiveRecord::Base

  belongs_to :user
  belongs_to :response

end

class Vote < ActiveRecord::Base

  belongs_to :user
  belongs_to :response

  validates :user, uniqueness: {  scope: :response,
                                  message: "User can only vote on this response once."}
end

Resolve merge conflict by keeping validations that prevent users from voting on more than one response per question.
Resolve merge conflict by keeping validations that prevent users from voting on more than one response per question.
