void SignInMenu()
        {
            Console.Write("Please enter your username: "******"\nLooks like the username you have entered doesn't exist. What would you like to do?\n");
                string[] badUsernameOptions = { "Use a Different Username", "Create an Account", "Exit" };
                switch (ChooseOptionFromList(intro: badUsername, options: badUsernameOptions))
                {
                //if sign-in is successful, move to main menu, otherwise, stay in sign in menu
                case 0: break;   //stays in current menu

                case 1: currentMenu = Menu.Signup;
                    break;

                case 2: Environment.Exit(0);
                    break;
                }
            }
            else
            {
                //sign-in was successful
                currentMenu = Menu.Main;
            }
        }