static function init()
 {
     if (!DatabaseManager::$isInit) {
         $dbname = $_SERVER["DOCUMENT_ROOT"] . '/database/perroquet.sqlite';
         DatabaseManager::$base = new SQLite3($dbname);
         if (DatabaseManager::$base == null) {
             echo "SQLite NOT supported.\n" . '<br/>';
             exit($err);
         }
         DatabaseManager::$isInit = true;
     }
 }