In a dutch oven, heat oil, add onion, carrot and celery. Cook over medium heat for 8 - 10 minutes or until onion is transparent. Remove mixture, add lamb cubes and brown on all sides. Return onion mixture to the pan. Combine turmeric, salt, pepper and red pepper flakes. Sprinkle over meat and vegetables, toss to combine. Add chicken broth, bring to a boil. Reduce heat to medium low and cook covered for 1 hour. After one hour, add chickpeas and cook uncovered for an addition 1 1/2 hours, stir occasionally. Add tomato paste, lime juice, vinegar and brown sugar. Cook until thickened approx. 30 - 40 minutes. Stir occasionally. Serve with rice.