Best Macaroni Salad

Ingredients:
- 8 ounces elbow macaroni (4 cups cooked)
- 1 (7 ounce) can tuna, drained (optional)
- 1 green pepper, chopped
- 1 tomatoes, chopped
- 1 cup low-fat mayonnaise
- 2 tablespoons vinegar
- 2 teaspoons prepared mustard
- 1 1/2 teaspoons salt
- 1/8 teaspoon pepper
- 1/2 teaspoon celery seed

Directions:
- Combine the macaroni, tuna, pepper and tomato.
- Mix together the mayonnaise, vinegar, mustard, salt, pepper and celery seeds, and stir into the macaroni mixture.
- Chill.