array1: [
    1 => array:1 [
         "category" => array2 [
                       "id" => 1
                       "category_name" => portable/fun
    ]
]

array1: [
    1 => array:1 [
         "category" => array2 [
                   "id" => 1
                   "category_name" => array:2 [
                                      1 => portable
                                      2 => fun
       ]
    ]
]