Author: Aparup Banerjee
assignment MDL-24694 - added message provider to manage assignment's messaging - user_preferences.name length changed form 50 to 255 due to long messaging preference names.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=39e171ac93a7e609c29e759425465a5949ed8ad8
http://github.com/moodle/moodle/commit/39e171ac93a7e609c29e759425465a5949ed8ad8
+ 2.0 en [messageprovider:assignment_updates,mod_assignment]