When the dog vomits

Our first dog vomited once when she first moved into our house. I didn't know what we did wrong at that time, we were just feeding her the right dog food, but she still vomited some yellow stuff. I researched about it and have found out that it might have been because of stress. She might have been stressed when she moved in because she was suddenly exposed to a different environment. Fortunately for our second dog, it didn't happen to her when she first moved in.