The goal of this example is to show you how you can author your own docker images using a parent image, making changes to it, and then saving the results as a new image. We will do that by making a simple hello flask web application image.
Inside of the "shykes/pybuilder" image there is a command called buildapp, we are running that command and passing the $URL variable from step 2 to it, and running the whole thing inside of a new container. BUILD_JOB will be set with the new container_id.
Save the changed we just made in the container to a new image called "_/builds/github.com/hykes/helloflask/master" and save the image id in the BUILD_IMG variable name.
view the logs for the new container using the WEB_WORKER variable, and if everything worked as planned you should see the line "Running on http://0.0.0.0:5000/" in the log output.