Grandma's Macaroni Salad

• 8 ounces elbow macaroni, cooked and drained
• 1 cup chopped celery
• 1/2 cup chopped green bell pepper
• 1/2 cup chopped red bell pepper
• 1/3 cup chopped onion
• 3/4 cup mayonnaise
• 2 tablespoons apple cider vinegar
• 1 tablespoon prepared mustard
• 1 teaspoon sugar
• 1 teaspoon salt
• 1/4 teaspoon ground black pepper