Developers say they broke ground Friday on an 100% affordable housing apartment building in Highbridge. The 76 units on Ogden Avenue will be priced around 30% to 80% of the neighborhood's median income, according to the developers. The ground floor will also have commercial and community space for tenants to use. The builders say quality of life is one of their big focuses as they get started on construction. Tax credits, loans and help from city agencies helped to finance the seven-story building.