@PostMapping("/add-user")
    public ResponseEntity<String> addUser(@RequestBody UserDto userDto) throws Exception {
        try {
            if (userDto.getFirstName().isEmpty() || userDto.getLastName().isEmpty() || userDto.getEmail().isEmpty() || userDto.getPassword().isEmpty()) {
                throw new Exception("Missing fields while adding a user.");
            }

    @PostMapping("/add-user")
    public ResponseEntity<String> addUser(@RequestBody UserDto userDto) throws Exception {
        try {
            if (userDto.getFirstName().isEmpty() || userDto.getLastName().isEmpty() || userDto.getEmail().isEmpty() || userDto.getPassword().isEmpty()) {
                throw new Exception("Missing fields while adding a user.");
            }