Added AlertManager ARM Dockerfile and openfaas label to armhf network

Signed-off-by: rgee0 <richard@technologee.co.uk>

contrib/alertmanager-armhf/0.15.0-rc.0/Dockerfile

@@ -0,0 +1,16 @@
+FROM alpine:3.6
+WORKDIR /root
+RUN apk add --update libarchive-tools
+ADD https://github.com/prometheus/alertmanager/releases/download/v0.15.0-rc.0/alertmanager-0.15.0-rc.0.linux-armv7.tar.gz /root/
+RUN bsdtar -xvf *.tar.gz -C ./ --strip-components=1
+RUN mkdir /etc/alertmanager
+
+RUN cp alertmanager               /bin/alertmanager
+RUN cp simple.yml    /etc/alertmanager/config.yml
+
+EXPOSE     9093
+VOLUME     [ "/alertmanager" ]
+WORKDIR    /alertmanager
+ENTRYPOINT [ "/bin/alertmanager" ]
+CMD        [ "-config.file=/etc/alertmanager/config.yml", \
+             "-storage.path=/alertmanager" ]

docker-compose.armhf.yml

@@ -208,3 +208,5 @@ networks:
     functions:
         driver: overlay
         attachable: true
+        labels:
+          - "openfaas=true"