rigatoni and italian sausage bake (potluck)

Ingredients

• 1/4 cup olive oil or salad oil
• 1 pound italian sausage (sliced)
• 1 large onion
• 1 clove garlic
• 1 large green pepper, yellow or orange chopped and cooked with onion and sausage
• 1 pound mushrooms (sliced)
• 1 pound rigatoni pasta
• 1/2 cup grated parmesan cheese
• 1/4 pound morzzarella cheese (cubed or sliced)
• 11/2 teaspoons salt
• 1/4 teaspoon pepper
• 1-6oz can tomato paste
• 3 cups water
• 1 teaspoon oregano
• 1 teaspoon sugar