/**
  * Handler for the confirm action.  Assigns a child cluster to specified cluster.
  */
 function action_subcluster()
 {
     global $CFG;
     $id = $this->required_param('id', PARAM_INT);
     $target_page = $this->get_new_page(array('id' => $id));
     $sub_cluster_id = $this->required_param('subclusterid', PARAM_INT);
     $cluster = new cluster($sub_cluster_id);
     $cluster->parent = $id;
     $cluster->update();
     redirect($target_page->get_url(), get_string('cluster_assigned', 'block_curr_admin'));
 }