tutorial was missing import

Author: chriscauley

README.md

@@ -58,6 +58,7 @@ To create a GraphQL schema for it you simply have to write the following:
 
 ```python
 from graphene_django import DjangoObjectType
+import graphene
 
 class User(DjangoObjectType):
     class Meta:

README.rst

@@ -68,6 +68,7 @@ following:
 .. code:: python
 
     from graphene_django import DjangoObjectType
+    import graphene
 
     class User(DjangoObjectType):
         class Meta: