Time for action – sending total count to all users

Perform the following steps to create our foundation logic for the game:

1. In the server folder, we create a new file named game.js. We will store the room and game logic in this file.
2. We define a User class that stores the socket connection object and creates a random ID.

   function User(socket) {
     this.socket = socket; 
     // assign a random number to User.
     // Long enough to make duplication chance less.
     this.id = "1" + Math.floor( Math.random() * 1000000000);
   }

3. We also define a Room class. We store a collection of user instances in this class.

   function Room() {
     this.users = []; 
   }

4. We define the two instance methods in the Room class that manages the adding and removing of users.

   Room.prototype.addUser = function(user){
     this.users.push(user); 
     var room = this; 
   
     // handle user closing
     user.socket.onclose = function(){
       console.log('A connection left.');
       room.removeUser(user);
     }
   };
   Room.prototype...