Storage API to update the directory info

[pyon-yx]

Hi, there.
I am now using fog-openstack project to call the OpenStack API.
Since I am working on the storage service part, I am going to call API to update the directory name and public status.
But https://github.com/fog/fog-openstack/blob/master/lib/fog/openstack/storage/models/directory.rb, here, I could not find the method to update the directory.
How can I create a method to update the directory info such as name and public status?