TEEN'S SHRIMP GUMBO

1/4 c. butter 1/2 c. onions, chopped 1/4 c. green pepper, chopped 1/8 tsp. garlic powder 2 tbsp. salt 1 tbsp. sugar 1 tsp. cornstarch 1/4 tsp. Tabasco 1 (1 lb.) can stewed tomatoes