-__PACKAGE__->meta->add_relationship(
-  unit_obj       => {
-    type         => 'many to one',
-    class        => 'SL::DB::Unit',
-    column_map   => { unit => 'name' },
+__PACKAGE__->meta->make_manager_class;
+
+__PACKAGE__->configure_acts_as_list(group_by => [qw(trans_id)]);
+
+__PACKAGE__->meta->add_relationships(
+  invoice          => {
+    type           => 'one to one',
+    class          => 'SL::DB::Invoice',
+    column_map     => { trans_id => 'id' },