cast extended models when loading from database

tests/DbTest.php

@@ -116,6 +116,8 @@ test("extending model",function()
     $row = $qbs->find(1);
     expect($row->id)->toBe(1);
     expect($row->col1)->toBe("test");
+
+    expect($row)->toBeInstanceOf(Test::class);
 });
 
 test("order by", function(){