Spray slow cooker with non-stick cooking spray. Take 2 tablespoons of brown sugar and rub on all sides of the roast; set roast in slow cooker.
In a medium bowl, mix together brown sugar, juice from can of pineapple rings, liquid smoke, and BBQ sauce. Pour of roast in slow cooker. Cook on low for 8-10 hours or high for 5-6 hours.
Using two forks, shred roast (it should literally fall apart). Scoop shredded pork onto individual rolls, top with a pineapple ring, and serve.