Application development with back-end and front-end

I need an application for "sales" - There is no checkout for payments. There are 3 user levels: Vendor, Distributor and Factory. Each of them will have an interface with access to the items available for sale. Basically, different types of ores. The interfaces are simple: The seller will see the items, as the price is per ton, will enter the quantity and the calculated value should appear right up front. If you agree, the item can be added to a shopping cart. Every time an item is added to the cart, an email must be sent to an administrator. Once all items are added to the cart, "we order". We generated a short report with the order information. If the merchant's product stock is not sufficient, an alert in the field where the value appears should show a message stating. This item will normally be added to the cart. If the Distributor's stock has that quantity, we subtract from that inventory the quantity and it will receive an email informing that an order has been made. If the stock of the distributor does not have enough stock, the factory is triggered, the item is added normally. The Distributor will have a panel similar to that of the seller. If there is no stock of a certain product, the item is automatically subtracted from the Factory, which will always have unlimited inventory of all orders. The factory panel will show all orders placed on all dealers and sellers. Each distributor will have a list of associated sellers. ALL DISTRIBUTORS WILL BE UNDER A SAME FACTORY. The project could be developed in Ruby, but I give preference to Node