Moroccan Beef Stew

• 3 tomatoes
• 2 garlic (cloves minced)
• 900 gr chuck roast
• 600 gr pineapple chunks
• 475 ml juice
• 130 gr carrots (sliced)
• 100 gr celery (chopped)
• 60 gr onion (chopped)
• 30 ml vegetable oil
• 24 gr flour