Coleslaw

3/4 cup mayonnaise

2 tablespoons sugar
1 teaspoon celery seed

3 tablespoons apple-cider vinegar
Salt and pepper

1 small head cabbage, cored, finely shredded
2 carrots, finely shredded

1/2 small red onion, thinly sliced
3 scallions, thinly sliced on the diagonal