feat(hook): add pre/post update hooks

Author: Gabriel Monroy

Dockerfile

@@ -6,6 +6,7 @@ ENV PATH /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local
 ENV GOPATH /go
 ADD . /go/src/github.com/deis/deisctl
 ADD units /tmp/package/var/lib/deis/units
+ADD hooks /tmp/package/var/lib/deis/hooks
 ADD deis-version /tmp/package/etc/deis-version
 WORKDIR /go/src/github.com/deis/deisctl
 RUN go get -v ./... && go install -v ./...

hooks/post-update

@@ -0,0 +1,2 @@
+#!/bin/bash
+exit 0

hooks/pre-update

@@ -0,0 +1,2 @@
+#!/bin/bash
+exit 0