int create_user(const char *name, User **user_ptr_add) {
    User *newUser = malloc(sizeof(User));
    strcpy(newUser->name, name);
    User *curr = *user_ptr_add;
    while (curr != NULL)
    {
        curr = curr->next;
    }
    curr->next = newUser;
    newUser-> = NULL;
}
adding user at the end of the linked list