Refs #19 - complete readme

README.rst

@@ -44,8 +44,18 @@ You can also use ``values()``:
     you'll have several small queries. This will save your RAM instead, because
     you'll not load a huge queryset result before looping on it.
 
+It is also possible to precise the field used for ordering:
+
+.. code:: python
+
+    from chunkator import chunkator
+    for item in chunkator(LargeModel.objects.all(), 200, order_by_field='pk'):
+        do_something(item)
+
+The field used for ordering **must** be defined as a Primary Key.
+
 
 License
 =======
 
-MIT License.
+MIT License.