Create tool to verify/validate built images and tags

[jdickey]

The tool must verify that:

1. All base images have been created correctly;
2. All tags pertinent to a given base image have been added exclusively to that base image;
3. All labels have been set correctly for each base image.

It Would Be Very Nice If the tool:

1. Verified that any given base image was in fact based on the OS version and Ruby version claimed. Several reads of the docker-api README and source do not indicate how to achieve this using the Docker API; shelling into each image appears to be necessary.

What is the difference between a "base image" and a "tag", you ask, when the Docker API itself makes no such distinction? We call the initial tag for an image (specified in the docker build command line or equivalent) the base image tag; all other tags are lagniappe.

Initial work towards this has been started; however, it should not delay the current in-progress update of the images.