In a slow-cooker, add all ingredients and toss to combine.
Cook on low for 3-4 hours
Near the end of the cooking time, use tongs to remove the cinnamon stick. Then use a wooden spoon to break up the cranberries. The sauce will thicken as it cools.
Notes
You can store leftovers in a sealed container in the refrigerator for 10-14 days. You can freeze the sauce for two months.