Crockpot Collard Greens

Ingredients

• 2 pounds fresh collard greens
• 1 tablespoon olive oil
• 1 onion, chopped
• 2 cup vegetable broth
• 3 cloves of garlic, minced
• ½ teaspoon red pepper flakes
• ¼ teaspoon ground black pepper
• 1 tablespoon vinegar
• 1/2 teaspoon salt