public function deleteDetail()
 {
     if (isset($_POST)) {
         $id = $_POST['id'];
         $det = DetailPenjualan::findOrFail($id);
         $penjualan = Penjualan::where('id', '=', $det->penjualan_id)->first();
         // dd($penjualan->id);
         if (DetailPenjualan::destroy($id)) {
             $barangs = DetailPenjualan::where('penjualan_id', '=', $penjualan->id)->get();
             $nominal = 0;
             foreach ($barangs as $key => $value) {
                 $nominal += $value->total;
             }
             $penjualan->nominal = $nominal;
             $penjualan->save();
         }
     }
 }