For most of the 20th century, Automat was a destination restaurant. At the gleaming coin-operated self-service restaurant, the chrome door opened, revealing comfortable dishes that go well with mom’s dishes. Correspondent Mo Rocca speaks with Lisa Frubitz, director of a new nostalgic documentary about the Horn & Hardart cafeteria chain. And with Broadway star Chita Rivera, she lovingly remembers her days as a dance student when the automat was away from home.