public function getPay($purchaseId)
    {
        $purchase = Purchase::findOrFail($purchaseId);

        if ($purchase->buyer->userId != Auth::user()->userId) {
            return redirect('/inventory/bought')->withErrors([
                "You are not the buyer of this item."
            ]);
        }

        if ($purchase->isPaid()) {
            return redirect('/inventory/bought')->withStatus(
                'You have already successfully paid for this item.'
            );
        }

        return view('mustard::purchase.pay', [
            'purchase' => $purchase,
        ]);
    }