delete_through_records

# File activerecord/lib/active_record/associations/has_many_through_association.rb, line 203
        def delete_through_records(records)
          records.each do |record|
            through_records = through_records_for(record)

            if through_reflection.collection?
              through_records.each { |r| through_association.target.delete(r) }
            else
              if through_records.include?(through_association.target)
                through_association.target = nil
              end
            end

            @through_records.delete(record)
          end
        end