Add some more stuff

docs/source/index.rst

@@ -69,7 +69,7 @@ You can also install Oscar API from source and run the sandbox site to play arou
     # run the server
     $ python sandbox/manage.py runserver
 
-Now you can browse the API at http://localhost:8000/api
+Now you can browse the API at http://localhost:8000/api. Here you can actually use the API already (a cool feature of `django-rest-framework`_) by using your browser and find out the different JSON formats you need to send.
 
 
 But I want to customise the standard serializers / views!
@@ -86,6 +86,7 @@ Probably you want this, because you already extended or changed Oscar's function
    usage/communicate_with_the_api
    usage/middleware
    usage/settings
+   usage/permissions
    usage/customizing_oscarapi
 
 .. Indices and tables