Healthy Slow Cooker Pulled Pork

boneless pork shoulder roast

cooking oil (I use avocado oil, but grapeseed or vegetable oil will work too)

large onion, diced

garlic, crushed

tomato paste

maple syrup

soy sauce (or gluten-free tamari)

chili powder (the Mexican-style spice mix)

apple cider vinegar

water

Salt and pepper,