Let's share recomender code on City.
Yon can add friend by click the ID on the list.
ID is checked once clicked, you can prevent duplicate registration.
You can share your ID to other peoples.
* How to use
1. Click the ID from the list.
2. When you click the ID will be copied to the clipboard. (Ctrl+C in a computer)
3. You can paste copied ID in the game.
4. Registered friends.