1.
Spread the sliced onion over the bottom of a slow cooker. Pour in the vinegar and water. Season the pork roast with salt and pepper to taste, then place into the slow cooker. Sprinkle the pork with brown sugar.
2.
Cover, and cook on Low until the pork is fall apart tender, about 8 hours.
3.
Once cooked, remove roast to a platter and allow to cool for about 10 minutes until cool enough to handle. Once cool, shred using two forks or your fingers. Discard gristle, bone, and excess fat.
4.
Pour off half of the liquid from the slow cooker, and add the shredded pork. Stir in the barbeque sauce to serve.