CLAUDIA CRISTOFERI ITALIAN fashion group Tod's said on Friday it appointed Instagram star and influencer Chiara Ferragni as a board member, stepping up its efforts to win over the younger shoppers fuelling the sector's growth. Shares in the luxury leather goods maker jumped more than 5% after the announcement about Ferragni, a 33-year-old Italian digital entrepreneur with over 23 million followers on her Instagram account where she shares fashion and style advice, as well as raising awareness on social issues. "We are sure that Chiara's knowledge of the world of young people, combined with the experience of the other board…