Sweet and Sour Crockpot Chicken

2 T ketchup
1 cup water
1/2 cup white vinegar
1 T soy sauce
1 cup brown sugar packed
1-1 1/2 1bs chicken breasts cubed

2 T cornstarch
2 T water

Combine first 5 ingredients, mix in crockpot, add chicken and cook on low for about 2 hrs (this is the tricky part, the first time watch how your crockpot cooks may need more or less time)
Combine the cornstarch and water and add to crockpot, cook addtional 15-20 min stiring often until thickened.
we serve over rice