Regenerate and fix docs
diff --git a/docs/reference/google.auth.rst b/docs/reference/google.auth.rst
index 6769e1c..2d50672 100644
--- a/docs/reference/google.auth.rst
+++ b/docs/reference/google.auth.rst
@@ -19,6 +19,7 @@
 
 .. toctree::
 
+   google.auth.app_engine
    google.auth.credentials
    google.auth.crypt
    google.auth.environment_vars