//...

  {
        method: "POST",
        path: "/v1/books",
        handler: (req, res) => {
            let newBook = new BookSchema(req.payload);

            newBook
                .save()
                .then(book => {
                    res(book).code(201);
                })
                .catch(err => {
                    res(err);
                });
        },
        config: {
            validate: {
                payload: {
                    title: Joi.string().required(),
                    author: Joi.string().required(),
                    price: Joi.number().required(),
                    tags: Joi.array()
                }
            }
        }
    }

//...