public function index()
{
$columns = ['checkbox', 'product', 'description', 'unit_cost'];
if (Auth::user()->account->invoice_item_taxes) {
$columns[] = 'tax_rate';
}
$columns[] = 'action';
return View::make('list', ['entityType' => ENTITY_PRODUCT, 'title' => trans('texts.products'), 'sortCol' => '4', 'columns' => Utils::trans($columns)]);
}