Jack Harlow, one of the most popular up-and-coming rappers in America, was in the spotlight at Churchill Downs when the 24-year-old delivered the 'Riders Up' call for this year's Kentucky Derby. The Louisville native made his visit to the races an all-day event by filming a music video for his new song entitled 'Churchill Downs.' Named a top new artist at last year's Billboard Music Awards, Harlow's popularity has skyrocketed this year after the release of his album Come Home The Kids Miss You, which includes his No. 1 hit...