I think the `DOCKER_OPTS` should be appended to `/etc/default/docker` and not replace the entire contents.
Upstream-commit: 81357e12e7a019c14d87dc491705ad92409293b7
Component: engine
* Added User Guide section outlines.
* Added User Guide to menu.
* Moved HTTPS example to articles.
* Replaced Hello World example with User Guide.
* Moved use cases out of examples.
* Updated Introduction to add User Guide.
* Redirected migrated /use and /articles links.
* Added Docker.io section
* Added Dockerized section
* Added Using Docker section
* Added Docker Images section
* Added Docker Links section
* Added Docker Volumes section
Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)
Upstream-commit: a7b2c4804b2d98c2b5622db40d3d70b88529d7fe
Component: engine
