Stock Manager Product - UseCases create a new product. (name, price_unit, amount = 0) find product (by id, name) get all product update a product (name, price_unit, amount) delete a product by id Customer - UseCases create a new customer. (name) find customer (by id, name) Sale - UseCases create a new Sale, it must have payment method and status, product sold and the customer find unique or many sales get history by date or between two dates with all sales