Git commits in Moodle 3.7.0 by Frédéric Massart

commit b91ddd160e29013a41a0d6b1efd22724c42ab9e1
Author: Frédéric Massart <fred@branchup.tech>
Date:   Fri, 20 Oct 2017 17:24:08 +0800
Tag:    v3.7.0-beta

MDL-60518 core_user: A user with ID 0 is never a real user