public function addOrder($column, $order = Grid::ORDER_ASC)
{
if (!in_array($column, $this->allowOrders)) {
throw new GridException('Wrong column order');
}
if (strtolower($order) != Grid::ORDER_ASC && strtolower($order) != Grid::ORDER_DESC) {
throw new GridException('Order for column "' . $column . '" is incorrect');
}
$column = $this->applyAlias($column);
$this->orders[$column] = $order;
}