How lucky can two guys be? Dustin Johnson's relationship with Paulina Gretzky is already well-documented but he isn't the only one in the family "dating up." Introducing Austin Johnson's girlfriend Sam Maddox. Sam play tennis at the College of Charleston in South Carolina and is the owner of a pretty solid little golf swing...rumor has it, compliments of Austin. Here's a look at some of Sam's hottest Instagram pics.