def add_to_cart(pid, quantity, cart):
c = Contains(quantity=quantity, order=cart, product_id=pid)
c.save()
p = Product.objects.get(id=pid)
r = p.stock_quantity
s = int(c.quantity)
p.stock_quantity=(r - s)
p.save()
def add_to_cart(pid, quantity, cart):
c = Contains(quantity=quantity, order=cart, product_id=pid)
c.save()