Add unittest to check for specific repo files

[thinkingserious]

This repo should have the following list of files included:

• ./Docker or docker/Docker
• ./docker-compose.yml or ./docker/docker-compose.yml
• ./.env_sample
• ./.gitignore
• ./.travis.yml
• ./.codeclimate.yml
• ./CHANGELOG.md
• ./CODE_OF_CONDUCT.md
• ./CONTRIBUTING.md
• ./.github/ISSUE_TEMPLATE
• ./LICENSE.md
• ./.github/PULL_REQUEST_TEMPLATE
• ./README.md
• ./TROUBLESHOOTING.md
• ./USAGE.md
• ./USE_CASES.md

This PR is only asking for tests of the existence of these files, if the files do not exist when you run the tests - do not worry about the tests not passing. We will identify this and create a new PR for the issue.
Thank you!

[pjhampton]

I've got this 👍

[AnnaDodson]

I've updated the file structure as per issue #528: removed USE_CASES.md and created directory use-cases so the test will definitely fail. I'm happy to update the tests once the PR has been merged if you would like to assign to me or if @pjhampton wants to.

[pjhampton]

Hey @AnnaDodson. Thanks. Feel free to update the code as you feel fit 👍