/**
  * Initialise the database from the config settings.
  */
 public static function init()
 {
     if (self::$connected) {
         return;
     }
     self::$connection = mysqli_connect(Config::getDatabaseHost(), Config::getDatabaseUser(), Config::getDatabasePassword(), Config::getDatabaseName());
     if (mysqli_connect_errno() != 0) {
         throw new DatabaseException(mysqli_error(self::$connection));
     }
     self::$connected = true;
 }