Barbeque Sauce

1 onion, chopped
2 Tbsp. oil
2 Tbsp. vinegar
2 Tbsp. brown sugar
1/4 cup lemon juice
1 cup ketchup
3 Tbsp. worcestershire sauce
1/2 cup water
1/2 tsp. prepared mustard
1/2 cup chopped celery

Brown onion in oil. Add remaining ingredients and simmer for 30 minutes.