class ActiveAdmin::Namespace

def register(resource_class, options = {}, &block)

namespace instance.
use the global registration ActiveAdmin.register which delegates to the proper
Register a resource into this namespace. The preffered method to access this is to 
def register(resource_class, options = {}, &block)
  config = find_or_build_resource(resource_class, options)
  # Register the resource
  register_resource_controller(config)
  parse_registration_block(config, &block) if block_given?
  reset_menu!
  # Dispatch a registration event
  ActiveSupport::Notifications.publish ActiveAdmin::Resource::RegisterEvent, config
  # Return the config
  config
end