router.post('/', (req,res,next)=>{
    const product = new Product({
        _id: new mongoose.Types.ObjectId(),
        name: req.body.name,
        price: req.body.price
    });
    product
    .save()
    .then(result =>{
        res.status(201).json({
        message: 'Handling POST requests to /products',
        createdProduct: product
        });
    })
    .catch(err => {
        res.status(500).json(error: err.message);
    });

});