Myrna's Baked Beans

1 cup chopped green peppers
1 cup chopped onion
1 cup chopped celery
2 lbs browned hamburger
4 Tbsp molasses
2 cans pork and beans
2 tsp dry mustard
2 Tbsp brown sugar
1 cup catsup
2 small cans tomato sauce

-Brown first 3 ingredients in 1 Tbsp oil
-Mix last six ingredients together in heavy pan
-Add browned vegetables and hamburger
-Simmer for 30 minutes, stirring often, or place in slow cooker on low for several hours