Add JSON example

docs/source/configuration.rst

@@ -1289,6 +1289,10 @@ This setting enables the second mechanism, otherwise by default the first will b
 A default JSON encoded list of objects must be returned. Each object
 corresponds to a matched user and needs the keys ``id`` and ``fullname``.
 
+.. code-block:: javascript 
+
+    [{"id": "foo", "fullname": "Foo McFoo"}, {"id": "bar", "fullname": "Bar McBar"}]
+
 .. note::
     Make sure your server script sets the header `Content-Type: application/json`.