Merge pull request #413 from ldeluigi/master

Fix #402

Author: jrief

adminsortable2/admin.py

@@ -487,7 +487,7 @@ def save_new(self, form, commit=True):
         obj = super().save_new(form, commit=False)
 
         order_field_value = getattr(obj, self.default_order_field, None)
-        if order_field_value is None or order_field_value >= 0:
+        if order_field_value is None or order_field_value < 0:
             max_order = self.get_max_order()
             setattr(obj, self.default_order_field, max_order + 1)
         if commit: