Adding doc.go files for packages
diff --git a/openstack/identity/v3/tokens/doc.go b/openstack/identity/v3/tokens/doc.go
index 02fce0d..76ff5f4 100644
--- a/openstack/identity/v3/tokens/doc.go
+++ b/openstack/identity/v3/tokens/doc.go
@@ -1,6 +1,6 @@
-/*
-Package tokens defines operations performed on the token resource.
-
-Documentation: http://developer.openstack.org/api-ref-identity-v3.html#tokens-v3
-*/
+// Package tokens provides information and interaction with the token API
+// resource for the OpenStack Identity service.
+//
+// For more information, see:
+// http://developer.openstack.org/api-ref-identity-v3.html#tokens-v3
package tokens