D.C. United today announced that the club has signed Gambian midfielder Sainey Nyassi. The 24-year-old joins United after playing seven seasons with the New England Revolution, and will occupy a domestic spot on United’s roster. Nyassi will also be available for selection for the Black-and-Red’s third-round Lamar Hunt U.S. Open Cup match at USL PRO affiliate the Richmond Kickers tonight at 7 p.m. “We are pleased to add Sainey to our roster,” said D.C. United General Manager Dave Kasper. “He possesses