Add multiplayer (Online) function for ios Game (Dots & Boxes)

Hi, I have the Source code for an ios game like this : [login to view URL] , the classic "Dots & Boxes" game, every thing in the game is done , the game is working perfect but now you can play against computer only, so I want to add multiplayer feature to the game , by using Faceebook or Game Center . The developer just have to do this function, and it's should work . So I Expect after the project done , the user can play online multiplayer via friends or randomly by using facebook or Game Center . -If You need more information , feel free to PM .