Updated to handle user address when server behind other services

lib/realtime.js

@@ -632,7 +632,7 @@ function connection(socket) {
     //create user data
     users[socket.id] = {
         id: socket.id,
-        address: socket.handshake.address,
+        address: socket.handshake.headers['x-forwarded-for'] || socket.handshake.address,
         'user-agent': socket.handshake.headers['user-agent'],
         color: color,
         cursor: null,