Hungry Jack Casserole

1 pound hamburger
1 chopped onion
2 tablespoons brown sugar
Salt, to taste
3/4 cup shredded cheese
1/2 cup barbecue sauce
1 (1 pound 12 ounce) can pork and beans
1/2 cup catsup
1 tablespoon Worcestershire sauce
2 tablespoons vinegar
1 can Hungry Jack