docs: added README for dockerhub

[patrickjcasey]

I added a new folder to the top level of the repo third-party-docs and added README-dockerhub.md file with a README that can be added to mitre/hipcheck page on dockerhub. I am not sure if we want to make another top-level directory, but I did not want to clutter the root of the repository with something that is only for Dockerhub. If anyone has suggested alternatives, please let me know!

I could not find any information for adding/editing the description via any official Docker tooling, but I found this link if we want to add this to CI to be run after deploying the latest image to Dockerhub

As far as adding tags, there did not seem to be an automated way of doing it. This link shows how to adjust the settings for the project and also contains the Categories supported by Dockerhub. I would propose that we add the following tags to the mitre/hipcheck image:

• Security
• Integrations & Delivery (if hipcheck is ever designed to be run in CI/CD pipelines)

[alilleybrinker]

Thanks @patrickjcasey! I have a few nitpick comments that should be quick fixes.

As for the location of the file, I'm inclined to instead name any top-level folder with files necessary for distributing Hipcheck something like dist/. This would keep with the generally short naming convention of other top-level folders. Within that folder, it would probably be good to split up the content based on the use, so putting it at dist/dockerhub/README.md would make sense.

Regarding the Category topic, I've pinged Amndeep to see if he can set the "Security" category for us.

[alilleybrinker]

Oh, and we probably should just use this GitHub Action (https://github.com/peter-evans/dockerhub-description) for setting the description. Under the hood it uses a Docker Hub API token to make the relevant API call for setting the description. This way we can update it ourselves whenever we need to instead of needing to ping Amndeep.

[patrickjcasey]

I preliminarily added the job to CI to automatically update the description. I don't think there is a way to test it works without actually pushing something to dockerhub. Also, I was not 100% certain that dockerhub credentials are the same as the credentials used for the docker cli

[patrickjcasey]

Also it should be noted somewhere that dockerhub limits the description to 25,000 bytes and the github-action plugin we are using automatically performs the truncation if necessary

[alilleybrinker]

Also it should be noted somewhere that dockerhub limits the description to 25,000 bytes and the github-action plugin we are using automatically performs the truncation if necessary

Good to note. We probably ought to error out rather than silently truncating. Likely means checking the byte length ourselves.

[alilleybrinker]

Thanks @patrickjcasey! 🎉