It’s a bold undertaking to make a documentary about one's own mother, especially a mother as world renowned as writer, director, and bon vivant Nora Ephron. However, Jacob Bernstein did so masterfully with the debut of Everything Is Copy. The HBO documentary celebrated its New York premiere last night at The Museum of Modern Art, where Mr. Bernstein was joined by a slew of Ms. Ephron’s long time collaborators and fans alike to celebrate her legacy before her passing in 2012.