Jay Z is adding another superstar to the Roc Nation Sports roster. The hip-hop mogul just signed one of Europe's hottest soccer players, Jerome Boateng, to his management company. Boateng is a defender for Bayern Munich, one of Germany's best teams. The 26-year-old becomes the first soccer star and European to join the Roc Nation Sports family, which includes athletes such as Kevin Durant, Victor Cruz, and Skylar...