Level 73
@heimdall what type of field is your category_id? If it is an integer, you might need to loop through the array and persist a row for each of the categories:
foreach(request("categorybox") as $category_id)
{
$category_dish = new category_dish();
$category_dish->category_id = $category_id;
$category_dish->dish_id = $Dishs->id;
$category_dish->save();
}
And I would guess that you are validating that at least one checkbox is selected, otherwise nothing will be saved here.