I don't get it about why I need product_id in my stocks relation manager like that? stock relation manager ``` protected static string $relationship = 'stocks'; ->headerActions([ Tables\Actions\CreateAction::make() ->using( fn(array $data, string $model): Model => $model::create([ 'product_id' => $this->ownerRecord->id, 'remaining_stock' => 0, 'price' => $data['price'] ?? 0, 'cost' => $data['cost'] ?? 0, 'adding_stock' => 0, 'profit' => $data['profit'] ?? 0, 'total_price' => 0, // This will be calculated later ]) ) ->slideOver() ->label('Add New') ->icon('heroicon-o-plus') ->modalWidth(MaxWidth::Large), ]) ```