App Component: Connecting to the Back-end

Set up the default opening state

To start, we’ll create the sign-in page as the default opening state. We do this by setting the gameStatus state property to be logged out. The `SignInScreen takes a callback function that will be called when the user clicks on the “Start a Game” button. That function must take two arguments: a user name and a language. For now, we can just accept it and log it to the console.