Update index.rst - Fix Error: Reverse for 'avatar_change' not found.

Author: PetrDlouhy

docs/index.rst

@@ -55,7 +55,7 @@ that are required. A minimal integration can work like this:
 4.  Somewhere in your template navigation scheme, link to the change avatar
     page::
 
-        <a href="{% url 'avatar_change' %}">Change your avatar</a>
+        <a href="{% url 'avatar:change' %}">Change your avatar</a>
 
 5.  Wherever you want to display an avatar for a user, first load the avatar
     template tags::