Buffalo Wing Soup

This is modified from A Year of Crockpotting, which is a really fun blog:

-2 cups cubed chicken
--1/2 yellow onion, chopped
--3 stalks celery, chopped
--1/4 cup unsalted butter
--1/4 cup flour
--2 cups 1% milk
--3/4 cup chicken broth
--4 oz Velveeta
--1/2 cup hot wing sauce

Mix melted butter and flour. Put everything in crockpot on low for 8 hours.