Dice the onion, and place in the slow cooker. Add minced garlic. Then add, tomatoes, tomato paste, brown sugar, vinegar, bay leaves, basil, oregano, and pepper. Stir well to combine. If your crock pot has a tendency to dry things out, add in 1 c water, depending thickness preferred. Put on the lid and cook on low for 6-8 hours. After cooking time, stir the sauce and season with salt (approx 1 teaspoon)