Bonus Challenge

Bonus Challenge #1: Create a controller for your Promotions model. You will have to hone your googleFu and figure out what the controller is and how to add one.
You will create the controller file so that your partners route will look like this:
//import your controller like any other module
const promotionsController = require("../controllers/promotions");

promotionRouter.route('/')
.get(PromotionsController.getPromotions)
.post(PromotionsController.createPromotion)
.put(PromotionsController.updatePromotions)
.delete(PromotionsController.deletePromotions);

promotionRouter.route('/:promotionId')
.get(PromotionsController.getPromotionById)
.post(PromotionsController.createPromotionById)
.put(PromotionsController.updatePromotionById)
.delete(PromotionsController.deletePromotionById);