add preliminary build tools for a Mail-in-a-Box PPA

Starting with my dnswl.org modifications to postgrey.

ppa/Makefile

+all:
+	# Clean.
+	rm -rf build
+
+	# Prepare to build source packages.
+	sudo apt-get install -y git dpkg-dev devscripts dput
+	mkdir -p build
+
+	# POSTGREY
+
+	# Download our fork of the Debian postgrey package.
+	git clone https://github.com/mail-in-a-box/postgrey build/postgrey
+
+	# Download the corresponding upstream package.
+	wget -O build/postgrey_1.35.orig.tar.gz http://postgrey.schweikert.ch/pub/postgrey-1.35.tar.gz
+
+	# Build the source package.
+	sudo apt-get build-dep -y postgrey
+	(cd build/postgrey; dpkg-source -b .)
+	(cd build/postgrey; dpkg-buildpackage -S -us -uc -nc)
+
+	# Sign the packages.
+	debsign build/postgrey_1.35-1miab1_source.changes
+
+	# Upload to PPA.
+	dput ppa:mail-in-a-box/ppa build/postgrey_1.35-1miab1_source.changes
+
+	# Clear the intermediate files.
+	rm -rf build/postgrey
+

ppa/README.md

+ppa instructions
+================
+
+Mail-in-a-Box maintains a Launchpad.net PPA ([Mail-in-a-Box PPA](https://launchpad.net/~mail-in-a-box/+archive/ubuntu/ppa)) for additional deb's that we want to have installed on systems.
+
+Packages
+--------
+
+* [postgrey](https://github.com/mail-in-a-box/postgrey), with a modification to whitelist senders that are whitelisted by [dnswl.org](https://www.dnswl.org/) (i.e. don't greylist mail from them).
+
+Building
+--------
+
+To rebuild the packages in the PPA, you'll need to be @JoshData.
+
+First:
+
+* You should have an account on Launchpad.net.
+* Your account should have your GPG key set (to the fingerprint of a GPG key on your system matching the identity at the top of the debian/changelog files).
+* You should have write permission to the PPA.
+
+To build:
+
+	# Start a clean VM.
+	vagrant up
+
+	# Put your signing keys (on the host machine) into the VM (so it can sign the debs).
+	gpg --export-secret-keys | vagrant ssh -- gpg --import
+
+	# Build & upload to launchpad.
+	vagrant ssh -- "cd /vagrant && make"
+
+To use on a Mail-in-a-Box box, add the PPA and then upgrade packages:
+
+	apt-add-repository ppa:mail-in-a-box/ppa
+	apt-get update
+	apt-get upgrade
+

ppa/Vagrantfile

+# -*- mode: ruby -*-
+# vi: set ft=ruby :
+
+Vagrant.configure("2") do |config|
+  config.vm.box = "ubuntu14.04"
+  config.vm.box_url = "http://cloud-images.ubuntu.com/vagrant/trusty/current/trusty-server-cloudimg-amd64-vagrant-disk1.box"
+
+  config.vm.provision :shell, :inline => <<-SH
+    sudo apt-get update
+SH
+end