Update Dockerfile for testing

Dockerfile-test

@@ -1,14 +1,14 @@
 FROM ubuntu
-RUN apt-get update && apt-get -y install unzip make git-core
-ARG consul_version
-ARG vault_version
-ARG go_version
-COPY consul_${consul_version}_linux_amd64.zip /tmp
-COPY vault_${vault_version}_linux_amd64.zip /tmp
-COPY go${go_version}.linux-amd64.tar.gz /tmp
-RUN unzip /tmp/consul_${consul_version}_linux_amd64.zip -d /usr/local/bin
-RUN unzip /tmp/vault_${vault_version}_linux_amd64.zip -d /usr/local/bin
-RUN tar -C /usr/local -x -f /tmp/go${go_version}.linux-amd64.tar.gz
+RUN apt-get update && apt-get -y install make git-core unzip
+ARG consul_version=1.0.6
+ARG vault_version=0.9.6
+ARG go_version=1.10.3
+ADD https://releases.hashicorp.com/consul/${consul_version}/consul_${consul_version}_linux_amd64.zip /usr/local/bin
+ADD https://releases.hashicorp.com/vault/${vault_version}/vault_${vault_version}_linux_amd64.zip /usr/local/bin
+ADD https://dl.google.com/go/go${go_version}.linux-amd64.tar.gz /usr/local
+RUN cd /usr/local/bin && unzip consul_${consul_version}_linux_amd64.zip
+RUN cd /usr/local/bin && unzip vault_${vault_version}_linux_amd64.zip
+RUN cd /usr/local && tar xf go${go_version}.linux-amd64.tar.gz
 ENV PATH=/usr/local/go/bin:/root/go/bin:$PATH
 WORKDIR /root/go/src/github.com/fabiolb/fabio
 COPY . .