Specify settings in the example app command. Fixes #180

Author: jerel

README.rst

@@ -99,7 +99,7 @@ Running the example app
 
     $ git clone https://github.com/django-json-api/django-rest-framework-json-api.git
     $ cd django-rest-framework-json-api && pip install -e .
-    $ django-admin.py runserver
+    $ django-admin.py runserver --settings=example.settings
 
 Browse to http://localhost:8000