Chris Rigg put pen to paper on a new three-year contract at Sunderland yesterday. The midfielder’s future was in major doubt as he headed towards the second of his two-year scholarship deal on Wearside. Rigg was able to sign a professional contract on his 17th birthday last month, but Sunderland faced huge competition from some of the biggest clubs in the world for his signature. The 17-year-old was said to be wary about extending his stay until the club had appointed a new manager, and it took only a matter of days after meeting Regis Le Bris that he was convinced to remain at the Stadium of …