Adding doc.go files for packages
diff --git a/openstack/networking/v2/extensions/external/doc.go b/openstack/networking/v2/extensions/external/doc.go
index d244f26..dad3a84 100755
--- a/openstack/networking/v2/extensions/external/doc.go
+++ b/openstack/networking/v2/extensions/external/doc.go
@@ -1 +1,3 @@
+// Package external provides information and interaction with the external
+// extension for the OpenStack Networking service.
 package external