Fixed vulnerabilities in Docker image.

- Updated to debian testing (stretch).
- Updated to go v1.7.
- Added .dockerignore file.

.dockerignore

@@ -0,0 +1,3 @@
+node-feature-discovery
+node-feature-discovery-job.json
+vendor/

Dockerfile

@@ -1,5 +1,31 @@
-FROM golang:1.6
+# Taken from https://github.com/docker-library/golang/blob/master/1.6/Dockerfile 
+# to build our golang image with debian testing (stretch).
+FROM buildpack-deps:stretch-scm
 
+# gcc for cgo.
+RUN apt-get update && apt-get install -y --no-install-recommends \
+		g++ \
+		gcc \
+		libc6-dev \
+		make \
+	&& rm -rf /var/lib/apt/lists/*
+
+ENV GOLANG_VERSION 1.7.1
+ENV GOLANG_DOWNLOAD_URL https://golang.org/dl/go$GOLANG_VERSION.linux-amd64.tar.gz
+ENV GOLANG_DOWNLOAD_SHA256 43ad621c9b014cde8db17393dc108378d37bc853aa351a6c74bf6432c1bbd182
+
+RUN curl -fsSL "$GOLANG_DOWNLOAD_URL" -o golang.tar.gz \
+	&& echo "$GOLANG_DOWNLOAD_SHA256  golang.tar.gz" | sha256sum -c - \
+	&& tar -C /usr/local -xzf golang.tar.gz \
+	&& rm golang.tar.gz
+
+ENV GOPATH /go
+ENV PATH $GOPATH/bin:/usr/local/go/bin:$PATH
+
+RUN mkdir -p "$GOPATH/src" "$GOPATH/bin" && chmod -R 777 "$GOPATH"
+WORKDIR $GOPATH
+
+# Build node feature discovery and set it as entrypoint.
 ADD . /go/src/github.com/kubernetes-incubator/node-feature-discovery
 
 WORKDIR /go/src/github.com/kubernetes-incubator/node-feature-discovery