feat(Dockerfile): add kubectl to the image

Author: mboersma

README.md

@@ -16,6 +16,7 @@ creating [issues][] and submitting [pull requests][].
 * [golint][]: go source code linter
 * [gox][]: simple go cross-compiling tool
 * [jq][]: command-line JSON processor
+* [kubectl][]: Kubernetes command-line client
 * [shellcheck][]: static analysis for shell scripts
 * [test-cover.sh][]: test coverage for multiple go packages
 * [upx][]: executable packer
@@ -56,6 +57,7 @@ The latest deis/go-dev Docker image is available at:
 [gox]: https://github.com/mitchellh/gox
 [issues]: https://github.com/deis/docker-go-dev/issues
 [jq]: https://stedolan.github.io/jq/
+[kubectl]: https://kubernetes.io/docs/user-guide/kubectl-overview/
 [official go Docker image]: https://hub.docker.com/_/golang/
 [pull requests]: https://github.com/deis/docker-go-dev/pulls
 [Quay.io]: https://quay.io

rootfs/Dockerfile

@@ -3,6 +3,7 @@ FROM quay.io/deis/base:v0.3.6
 ENV GO_VERSION=1.8.3 \
     GLIDE_VERSION=v0.12.3 \
     GLIDE_HOME=/root \
+    KUBECTL_VERSION=v1.6.4 \
     SHELLCHECK_VERSION=v0.4.6 \
     PATH=$PATH:/usr/local/go/bin:/go/bin:/usr/local/bin/docker \
     GOPATH=/go
@@ -29,6 +30,8 @@ RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
   && curl -sSL -o /tmp/protoc.zip https://github.com/google/protobuf/releases/download/v3.1.0/protoc-3.1.0-linux-x86_64.zip \
   && unzip /tmp/protoc.zip 'bin/protoc' -d /usr/local \
   && rm /tmp/protoc.zip \
+  && curl -sSL https://storage.googleapis.com/kubernetes-release/release/$KUBECTL_VERSION/bin/linux/amd64/kubectl -o /usr/local/bin/kubectl \
+  && chmod +x /usr/local/bin/kubectl \
   && apt-get purge -y --auto-remove \
     unzip \
   && apt-get autoremove -y \