Modernista! said it has added Julie Teninbaum as a designer. Teninbaum, 32, will work on a variety of the Boston-based agency’s clients including the recently added Rockport shoe business. Prior to joining Modernista!, Teninbaum headed her own design firm, The Fan Club. She also worked as a junior art director with Random House and as a designer with Penguin Books, both in New York. Teninbaum began her career with JWG in Wellesley, Mass.