Fixed #20305 - Added include for polls/static to MANIFEST.in in tutorial.

Thanks monuszko for the report.

docs/intro/reusable-apps.txt

@@ -223,6 +223,7 @@ Create a file ``django-polls/setup.py`` with the following contents::
 
     include LICENSE
     include README.rst
+    recursive-include polls/static *
     recursive-include polls/templates *
 
 7. It's optional, but recommended, to include detailed documentation with your