Place half of the onion rings in crockpot. Add the roast and then the rest of onions. Pour in 1 cup of ginger ale. Cover and cook on Low for 8-10 hours, or until pork can be easily shredded.
Remove pork from pot and shred. Remove onions and add to shredded pork in a bowl. Discard juice in pot. Return onions and pork to pot, add barbecue sauce and mix. Continue to cook on LOW for 3-4 hours.
Makes great barbecue sandwiches.
Freeze leftovers in ice cube trays. When frozen, remove to zip bags. Thaw 2-3 cubes for sandwich; 1 for baked potato topping; 2-3 for barbecue pork pasta.