bump docker to v0.9.0
Merge pull request #90 from opdemand/548-update-docker

bump docker to v0.9.0
Remove version lock on chef-docker

Now that we're using Docker 0.9.0, we should resume using the latest
chef-docker release. I locked this to 0.31 because 0.32 introduced
breaking changes for those still using Docker 0.8.0.
We don't need Berksfile.lock
Merge pull request #96 from opdemand/carmstrong/remove_chef-docker_lock

Remove version lock on chef-docker
Add tests:
- rubocop
- knife cookbook test

Use strainer to launch test:
$ bundle exec strainer test
rubocop autocorrect
Fix rubocop
Fix all Foodcritic
Change way of testing with rake instead of strainer

Add documentation
Change .gitignore to .gitkeep
Fix merge faux pas
Don't epic fail on FC014
Additional rubocop / foodcritic fixes