Objective The objective of this assignment is to extend the Address Book application developed in last lab task (Assignment 3) by implementing a user authentication system and role-based access control . Students will create a Signup and Login system and ensure that only authenticated users can perform Create, Update, and Delete operations. Application Requirements 1. Users Data Storage Create a new JSON file named auth-users.json .  This file will store registered users as an array of objects. You can also use mongodb database to store users data. Each user object must contain: id name email password Password hashing is not required for this assignment. 2. Signup (Registration) Feature Create /signup route. On GET request , display a signup form. Form fields: Name Email Password Confirm Password On POST request : Validate password and confirm password. Check if email already exists in auth-users.json . If validation fails, show an error message on signup page. If successful, ...