Place The Ground Beef And Chopped Onion In A Skillet Over Medium Heat; Cook And Stir Until The Beef Is Completely Browned And The Onions Are Translucent. Drain The Fat From The Skillet And Return It To Medium Heat. Stir In The Tomato Sauce, Ketchup, Brown Sugar, And Vinegar. Reduce Heat To Medium Low And Simmer 20 Minutes.