Tyronn Lue is joining the Celtics... as an assistantWALTHAM --  The Celtics hired NBA former point guard Tyronn Lue as their Director of Basketball Development on Friday. He will assist the coaching staff and observe practices. He made his debut on Friday in Waltham as the Celtics prepare for their season opener on Tuesday in Cleveland.Oh... I'm sorry... was that headline a little misleading?  Yeah... well... so was that "girl" at the bar last night... s...