concat_records

# File activerecord/lib/active_record/associations/collection_association.rb, line 417
        def concat_records(records, raise = false)
          result = true

          records.each do |record|
            raise_on_type_mismatch!(record)
            add_to_target(record) do
              unless owner.new_record?
                result &&= insert_record(record, true, raise) {
                  @_was_loaded = loaded?
                }
              end
            end
          end

          raise ActiveRecord::Rollback unless result

          records
        end