David Muir gave his fans a reason to be grateful and emotional this weekend as he shared an excerpt from one of his news segments on social media.MORE: David Muir's home photo during time away from GMA studios is too heartwarming for wordsThe Good Morning America journalist posted a clip from his evening news for ABC, where he told the story of a football team in Riverside, California.He shared that the California School for the Deaf in Riverside was making history as their varsity high school