feat(DockerFile): Install Docker in the image (#76)

* Install Docker in the container image

* Update ReadMe and pin to a Docker version

* Extract Docker binaries from tar file and set path

* Fix typo

* Update target directory to extract binaries in and upate executable permissions

Author: amanohar

README.md

@@ -19,6 +19,7 @@ creating [issues][] and submitting [pull requests][].
 * [shellcheck][]: static analysis for shell scripts
 * [test-cover.sh][]: test coverage for multiple go packages
 * [upx][]: executable packer
+* [Docker][]: Docker binaries to be able to bind mount /var/run/docker.sock in the dev environment container
 
 ## Usage
 
@@ -61,3 +62,4 @@ The latest deis/go-dev Docker image is available at:
 [shellcheck]: https://github.com/koalaman/shellcheck
 [test-cover.sh]: https://github.com/deis/docker-go-dev/tree/master/rootfs/usr/local/bin/test-cover.sh
 [upx]: http://upx.sourceforge.net/
+[Docker]: http://www.docker.com

rootfs/Dockerfile

@@ -4,7 +4,7 @@ ENV GO_VERSION=1.8.3 \
     GLIDE_VERSION=v0.12.3 \
     GLIDE_HOME=/root \
     SHELLCHECK_VERSION=v0.4.6 \
-    PATH=$PATH:/usr/local/go/bin:/go/bin \
+    PATH=$PATH:/usr/local/go/bin:/go/bin:/usr/local/bin/docker \
     GOPATH=/go
 
 RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
@@ -34,6 +34,10 @@ RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
   && apt-get autoremove -y \
   && apt-get clean -y \
   && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/* /usr/share/man /usr/share/doc \
+  && curl -fsSLO https://get.docker.com/builds/Linux/x86_64/docker-17.05.0-ce.tgz \
+  && tar xzvf docker-17.05.0-ce.tgz -C /usr/local/bin \
+  && chmod +x -R /usr/local/bin/docker \
+  && rm docker-17.05.0-ce.tgz \
   && go get -u -v \
   github.com/alecthomas/gometalinter \
   github.com/onsi/ginkgo/ginkgo \