8.5 Macaroni Salad

This got the husbands approval :-) Id rate it about an 8.5
1 cup mayonnaise
2 Tbs. vinegar
1 Tbsp. mustard powder
1 tsp. sugar
1 tsp. salt
1/8 tsp. pepper
2 sticks chopped celery
1 chopped onion
4 cups (when dry) cooked and drained macaroni
Mix and chill well before serving