Audi partners with Amazon for Tesla-killer, Postmates evolves into a unicorn (and plans IPO), and why General Mills stock dropped 7%

Summary: Cereal was killing General Mills -- But shares dropped 7% because it’s lost its 1 good thing. Postmates raised $300M to officially become a unicorn, so the CEO saddled up on some IPO plans. And Audi’s new electric SUV dropped Tesla’s stock -- and it’s partnered up with Amazon to convince you to buy one.