Describe building the debian package

Debian.md

@@ -1 +1,29 @@
-Welcome to the zfs-auto-snapshot wiki!
+Make ZFS Snapshots work on Debian
+=================================
+
+A `.deb` package can be created for `zfs-auto-snapshot` in just a few (manual) steps.
+
+As a non-root user do:
+
+Get the code:
+
+    $ cd /usr/src (or wherever you want to build the .deb)
+    $ git clone https://github.com/zfsonlinux/zfs-auto-snapshot.git
+
+Optional: If you want to expose snapshots via Samba's [vfs_shadow_copy2](https://www.samba.org/samba/docs/man/manpages/vfs_shadow_copy2.8.html) to Windows users as *shadow copies* you must merge this code first:
+
+    $ git checkout leecallen
+    $ git merge master
+    $ editor src/zfs-auto-snapshot.sh (manually fix a conflict)
+    $ git add .
+    $ git commit -a
+
+Get the debian-specific changes and build the `.deb`:
+
+    $ git merge origin/debian
+    $ dpkg-buildpackage -b -uc -us
+
+As root install the `.deb`:
+
+    $ sudo dpkg -i ../zfs-auto-snapshot_*.deb
+