Git commits in Moodle 3.0.0 by Dmitrii Metelkin

commit 6d6e297b1333e6e04af69743bb3783c14d3f2715
Author: Dmitrii Metelkin <dmitriim@catalyst-au.net>
Date:   Fri, 06 Nov 2015 12:21:01 +0800
Tag:    v3.0.0-rc4

MDL-51314 mod_assign: cache group membership in can_edit_submission