Warm-hearted people are accepting a Facebook challenge to jump into chilling water to raise money for Grundy County toddler Madilyn “Madi” Rogers, who is in need of a specially trained service dog.The Madi Rogers 24hr Cold Water Challenge has gone viral on Facebook. What started in Middle Tennessee has traveled around the country as people from North Dakota to Louisiana have posted online videos of themselves jumping into pools and lakes. One video shows two guys hosing themselves off at a car wash.According to the fundraiser, Madi is 2 years old and has juvenile diabetes.