Update Dockerfile

example/Dockerfile

@@ -1,7 +1,7 @@
 FROM alpine:latest
-RUN echo "http://dl-4.alpinelinux.org/alpine/edge/testing" >>/etc/apk/repositories && apk add --update runit && rm -rf /var/cache/apk/*
-
-ADD runsvinit /
+RUN echo "http://dl-4.alpinelinux.org/alpine/edge/testing" >>/etc/apk/repositories && \
+    apk add --update runit && \
+    rm -rf /var/cache/apk/*
 
 ADD foo /
 RUN mkdir -p /etc/service/foo
@@ -11,4 +11,5 @@ ADD bar /
 RUN mkdir -p /etc/service/bar
 ADD run-bar /etc/service/bar/run
 
+ADD runsvinit /
 ENTRYPOINT ["/runsvinit"]