If using fresh mushrooms instead of canned, saute in olive oil with a bit of extra garlic.
Cut Italian Sausage into 1 inch pieces. Brown in frying pan.
Chop zucchini into bite sized chunks.
Add all ingredients except tomato paste into slow cooker. Cook on low for 5+ hours.
30 minutes before serving, stir in tomato paste to help thicken juices.