Integrate Docker into the build

- Isolates us from the host -- no more accidentally using a feature
that's present on a newer distro but not the build machine; no more
relying on packages you didn't realize you installed
- Both continuous build and rootfs leverage this, as well as local
builds

Continuous and rootfs build results on Kokoro w/ this change:
- https://sponge.corp.google.com/target?id=c061e5b2-b94f-4056-bf25-c69e25a71ed3&target=spacepark/enterprise/continuous-test
- https://sponge.corp.google.com/target?id=d6f312f2-9610-4be1-b7f1-cc7e7c7db6d9&target=spacepark/enterprise/rootfs-test

Change-Id: I95b305054ed16269b83bbcbaf89d8b89d8628fad
diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 0000000..c7f1c12
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,17 @@
+FROM debian:9.4
+MAINTAINER support-aiyprojects@google.com
+
+# Install Docker into this image, so we can run nested containers for ARM64 builds.
+RUN apt-get update -qq && apt-get install -qqy \
+        apt-transport-https \
+        ca-certificates \
+        curl \
+        lxc \
+        iptables
+RUN curl -sSL https://get.docker.com/ | sh
+
+# Install the prerequisite packages into the image.
+ADD . /build
+RUN /bin/bash -c 'apt-get update && apt-get install sudo make && ln -sfr /build/Makefile /Makefile && source /build/setup.sh && make -C /build prereqs'
+
+VOLUME /var/lib/docker