update README for packer

buildozer/tools/packer/README.md

@@ -1,6 +1,7 @@
 # Introduction
 
-It is an example packer template based on netboot iso that adds packages for xubuntu and buildozer.
+This is the packer template for building the official Kivy/Buildozer VM.
+It is based on xubuntu.
 
 # Configure
 
@@ -8,14 +9,29 @@ You want to edit `http/preseed.cfg` and `template.json` before building an image
 
 # Build
 
-`packer build template.json`
+```
+make packer
+```
 
-# Testing the image after it's built.
+# Release
 
-`./launch`
+1. Update Makefile to increase the version number
+2. Update the CHANGELOG
+3. Commit
 
-# TODO
+Then:
 
-  - [compact the image](https://crysol.github.io/recipe/2013-10-15/virtualbox-compact-vmdk-images/)
-  - trigger a build on travis, torrent creation and gdrive upload when buildozer is released
-  - https://www.packer.io/docs/builders/virtualbox-ovf.html
+```
+make all
+# make packer       < build the image
+# make repackage    < just zip it (no compression)
+# make torrent      < create the torrent
+# make upload       < upload on txzone.net (tito only)
+```
+
+
+# Notes
+
+- trigger a build on travis, torrent creation and gdrive upload when buildozer is
+  released
+- https://www.packer.io/docs/builders/virtualbox-ovf.html