Walmart: a place to get all your back-to-school shopping done... if you're the protagonist of a post-apocalyptic YA novel. The retail giant is under fire after someone snapped a photo of a gun display in one of its stores underneath a sign that reads, "Own the school year like a hero." Since the photo went viral this week, the company has been scrambling to find out which of its stores put up the sign that many are calling offensive. Photo: Walmart's Website Described Product As 'N-Word Brown' After investigating the matter, Walmart reports that the sign seems to have been taken from a . . .