automatically remove models from sidebar that are inaccessible?

Created by: jmmastey

I have an administrate install with two types of users (admin and staff), authorized via Pundit.

Staff are not able to edit the record Neighborhoods, admins are. Example part of the policy:

class NeighborhoodPolicy
  def index?
    @user.admin?
  end
end

Really, staff can't do anything with neighborhoods, so I'd like to remove that link from the left navigation entirely. Would y'all be amenable to a PR that changes Administrate::Namespace.resources to check authorization of the index action and conditionally drop that from navigation?