add README.md

README.md

+# The su_debuild Puppet module
+
+## Overview
+
+The `su_debuild` Puppet classes will set up a complete Debian build
+systems on your Debian server. This includes chroots to allow for the use
+of `pbuilder` and gbp buildpackage`.
+
+## Installing the necessary packages
+
+If all you need are the packages and not the chroot environments, you do this:
+
+    include su_debian
+
+Note that this will allow you to run most of the Debian packaging commands
+including `dpkg-buildpackage` but not any of the commands that require a
+chroot.
+
+## Installing chroot environments
+
+To install chroot environments use the `su_debuild::chroots` class. For
+example, the following will setup the necessary packages and install
+chroot environments for Debian `sid`, `stretch`, `jessie`, and Ubuntu
+`bionic`
+
+    include su_debuild
+    class { 'su_debuild::chroots':
+      chroots => [ 'sid', 'stretch', 'jessie', 'bionic']
+    }
+
+The above also installs a daily cron job to update the chroots.