Adding directions for updating to 0.12.0 to UPGRADING

UPGRADING

                        Music Player Daemon (MPD) - UPGRADING
 
+Upgrading to 0.12.0
+-------------------
+
+The ao_driver and ao_driver_options config parameters have been removed and
+replaced with the audio_output config section.  You will have to update your
+config file to use this instead.  See the mpd.conf man page or the new
+mpdconf.example for details on specifying audio_output sections.
+
+The db_file parameter is no longer optional.  If you did not specify it in your
+old config file then you will have to add it in order to run 0.12.0.
+
+Support for OggFLAC and Musepack audio files has been added.  Additionally,
+scanning of MP3 files has been improved.  To make use of these updates it is
+highly recommended that you run mpd --create-db to recreate your entire
+database.
+
 Upgrading to 0.11.0
 -------------------