duplicates.rb

Survey.active.each do |survey|
  survey.response_sets.completed.each do |set|
    answer_ids = []
    set.responses.each do |r|
      if r.answer.blank?
        r.destroy
      else 
        puts "Response #{r.id}: set=#{set.id}, answer=#{r.answer.id}"
        if answer_ids.include? r.answer_id
          r.destroy
        else
          answer_ids << r.answer_id
        end
      end
    end
  end
end