title: Do docker containers retain file changes?
body: <p>This is a very basic question, but I'm struggling a bit and would like to make sure I understand properly.</p>
  
  <p>After a container is started from an image and some changes done to files within (i.e.: some data stored in the DB of a WebApp running on the container), what's the appropriate way to continue working with the same data between container stop and restart?</p>
  
  <p>Is my understanding correct that once the container is stopped/finished (i.e.: exit after an interactive session), then that container is gone together with all file changes?
  So if I want to keep some file changes I have to commit the state of the container into a new image / new version of the image?</p>