Open questions on container episode 2

[jcoliver]

• Do we need any information for instructors at the beginning of the episode (like in an instructor callout)?
• At the beginning of the Introduction (right before Dockerfiles section), there could be a visual, linking what we have done so far (running a container from a pre-built image) to what we are going to do (building an image, then using that to run a container).
• When we create the Dockerfile (presumably on the VM), where should we make the file? Is the home directory OK?