cleanup dockerfile

Signed-off-by: Martin Buchleitner <mabunixda@gmail.com>

Dockerfile

@@ -1,10 +1,12 @@
+#
+# building static go binary with golang container
+#
 FROM golang:stretch as builder
 
 RUN mkdir -p $GOPATH/pkg/mod $GOPATH/bin
 
 RUN apt-get update \
-  && apt-get install -y ruby ruby-dev curl  \
-  && gem install --no-document fpm \
+  && apt-get install -y curl  \
   && curl https://raw.githubusercontent.com/golang/dep/master/install.sh | sh \
   && mkdir -p $GOPATH/src/github.com/davidnewhall
 
@@ -12,14 +14,21 @@ COPY . $GOPATH/src/github.com/davidnewhall/unifi-poller
 WORKDIR $GOPATH/src/github.com/davidnewhall/unifi-poller
 
 RUN dep ensure \
-  && CGO_ENABLED=0 make build
+  && CGO_ENABLED=0 make linux
 
+#
+# creating container for run 
+# to use this container use the following command: 
+#
+# docker run -d -v /your/config/up.conf:/etc/unifi-poller/up.conf golift/unifi-poller
+#
+# by using "-e UNIFI_PASSWORD=your-secret-pasword" you can avoid this configuration in the config file
+#
 FROM scratch 
 
-COPY --from=builder /go/src/github.com/davidnewhall/unifi-poller/unifi-poller /unifi-poller
+COPY --from=builder /go/src/github.com/davidnewhall/unifi-poller/unifi-poller.linux /unifi-poller
 COPY --from=builder /go/src/github.com/davidnewhall/unifi-poller/examples/up.conf.example /etc/unifi-poller/up.conf
 
 VOLUME [ "/etc/unifi-poller"]
 
 ENTRYPOINT [ "/unifi-poller" ]
-CMD [ "--config=/etc/unifi-poller/up.conf" ]