Macaroni Salad

1 cup cooked elbow macaroni, cooled
1 hard-cooked egg, chopped
2 tablespoons chopped onion
3 tablespoons mayonnaise
1 teaspoon vinegar
1 teaspoon granulated sugar
1/4 teaspoon salt
1/4 teaspoon mustard Pepper to taste

Combine all ingredients, stirring lightly. Cover and chill several hours before serving.