public function postEdit(Request $request)
    {
        $item = Item::findOrFail($request->input('item_id'));

        if ($item->userId != Auth::user()->userId) {
            return redirect()->back()->withErrors(['You can only edit your own items.']);
        }

        if (!$item->isActive()) {
            return redirect()->back()->withErrors(['You can only edit an active item.']);
        }

        return redirect('/inventory/selling')
            ->withStatus($item->name.' has been edited.');
    }