Squashed 'docker/fluentd/' content from commit a8a47c7

git-subtree-dir: docker/fluentd
git-subtree-split: a8a47c72cc58d8e65eac4c845338a9d8f589e38d
Merge commit '15682dbd544d0f20d23c7a1f482c98bde994d201' as 'docker/fluentd'
added fluentd