Fixed invalid testing fixture

tests/fixtures_regress/fixtures/special-article.json

@@ -1,4 +1,10 @@
 [
+    {
+        "pk": 1,
+        "model": "fixtures_regress.article",
+        "fields": {"title": "foof"
+        }
+    },
     {
         "pk": 1,
         "model": "fixtures_regress.specialarticle",