It is the classic musical of modern times, a tour de force that has a back story just as tragic as the one that unfolds on stage, and, last night, Rent, the updated version of La Boheme, opened at the Old Rep Theatre Birmingham with a brilliant ensemble performance. Rent is the story of a group of artistic bohemians living in East Village, New York during the early 1990s. The talented bunch include a dancer (Mimi), a film-maker (Mark), a guitarist and lead singer (Roger), a transsexual woman (Angel) and a teacher turned anarchist (Tom Collins). They live an impoverished existence and, in the case of Mimi, Collins and Roger,…