Docs on changing the name of an ObjectType (#922)

Fixes https://github.com/graphql-python/graphene/issues/839

docs/types/objecttypes.rst

@@ -230,4 +230,17 @@ previous example you could do:
     peter.first_name # prints "Peter"
     peter.last_name # prints "Griffin"
 
+Changing the name
+-----------------
+
+By default the type name in the GraphQL schema will the same as the class name
+that defines the ``ObjectType``. This can be changed by setting the ``name``
+property on the ``Meta`` class:
+
+.. code:: python
+
+    class MyGraphQlSong(graphene.ObjectType):
+        class Meta:
+            name = 'Song'
+
 .. _Interface: /docs/interfaces/