Chanel Iman has found a musical match in A$AP Rocky. The model, 22, is said to be dating the 24-year-old, Harlem-born rapper of hits including “[Bleepin’] Problems” with Drake, 2 Chainz and Kendrick Lamar. “He’s a very sweet and gracious fella,” said a friend. Iman modeled in the Jason Wu show yesterday for Mercedes-Benz Fashion Week, where “Girls” actress Allison Wiliams and Jaime King sat front row. Iman is headed to DC next week to have lunch with Michelle Obama.