public static function add_default_relation($user_id, $network_info)
 {
     $extra = unserialize($network_info->extra);
     $relations_name = $extra['user_defaults']['user_friends'];
     if ($relations_name != '') {
         $relations = explode(',', $relations_name);
         $relations_ids = User::map_logins_to_ids($relations);
         $selected = DEFAULT_RELATIONSHIP_TYPE;
         //  2 for friends
         foreach ($relations_ids as $key => $value) {
             if (!Relation::relation_exists($user_id, (int) $value)) {
                 Relation::add_relation($user_id, (int) $value, $selected, PA::$network_info->address, PA::$network_info->network_id);
             }
         }
     }
 }