Explaining Drake and Pusha T's beef

On Tuesday, rapper Pusha T had a concert in Toronto interrupted by a brawl in the audience. Fans threw beer at him and tried to jump on stage. And now, a man is in life-threatening condition after being stabbed. Pusha T and Canadian rapper Drake have been in a public feud since last spring, and Pusha has accused Drake of paying members of the rowdy audience. Author and Drake biographer Dalton Higgins on how this beef developed.