public User LoginSignup(IProvideData DataProvider, string startingOption = "SignUp")
        {
            startingOption = SelectionMenu.Horizontal(new List <string> {
                "Login", "SignUp", "Exit"
            }, Headers.headerw).NameOfChoice;
            Console.Clear();
            if (startingOption == "Exit")
            {
                Environment.Exit(0);
            }

            string GivenUsername = ReadUsername();
            string GivenPassword = ReadPassword();

            if (startingOption == "SignUp")
            {
                User u1 = new User()
                {
                    Username       = GivenUsername,
                    Password       = GivenPassword,
                    UsersPrivilege = DataProvider.IsStorageEmpty() ? Privilege.admin : Privilege.user
                };

                Debug.Write("New User was created successfully: " + DataProvider.CreateUser(u1));
                return(u1);
            }
            else if (startingOption == "Login")
            {
                return(ValidLogin(GivenUsername, GivenPassword));
            }
            return(null);
        }
        public void CreateUser()
        {
            LoginOrSignup CreateNewUser = new LoginOrSignup(DataProvider);
            User          u2            = new User()
            {
                Username       = CreateNewUser.ReadUsername(),
                Password       = CreateNewUser.ReadPassword(),
                UsersPrivilege = Privilege.user
            };

            DataProvider.CreateUser(u2);
            Console.WriteLine($"User \"{u2.Username}\" has been created!");
        }