How to continue a Docker container which has exited

Consider:

docker run -it centos /bin/bash

I pressed Ctrl+D to exit it.

I want to continue to run this container, but I found I can’t.

The only method is

docker commit `docker ps -q -l` my_image
docker run -it my_image /bin/bash

Am I right? Is there a better method? (I’m using docker 0.8.0.)