add release howto

HOWTO.RELEASE

@@ -0,0 +1,40 @@
+How to release a new version of PhD
+-----------------------------------
+
+Releases are currently made from the PHD_0_4 branch.
+Changes in HEAD are merged back into that branch.
+
+0. Check if all changes in HEAD have been merged back to the release branch.
+
+1. Check if all changes have an entry in package.xml's <notes>.
+
+2. Check if the api version needs to be increased to match the release
+   version. (This is the case when the API has changed. Normally the
+   committer has done that already when merging from HEAD, but you'll
+   never know).
+   
+3. Make sure all files are listed in package.xml's <content>.
+
+4. Edit config.php and set PHD_VERSION to the current one.
+
+5. $ pear package
+   $ pear install PhD-*.tgz
+   .. try phd on phpdoc and peardoc ..
+   $ pear cvstag package.xml
+
+6. Upload the tgz to http://doc.php.net/up.php
+
+7. Test by installing from the channel:
+   $ pear upgrade -f doc.php.net/phd-$previousversion
+   $ pear upgrade doc.php.net/phd-$thisstability
+   .. try phd on phpdoc and peardoc ..
+
+8. Let Hannes update http://doc.php.net/phd/
+
+9. Send release mail to phpdoc@ and pear-doc@lists.php.net
+
+A. Remove all contents from <notes> and increase version/release.
+   Change stability back to "snapshot". Revert PHD_VERSION in
+   config.php back to "phd-from-cvs".
+
+B. Hack on.