@julian :wow! so efficient +1:

Bug Reproduce:
1.goto page /users/latest
2.click administrator user
3.click user group administrators
4.then raise this error
25/2 10:00 [19807] - info: NodeBB is now listening on: 0.0.0.0:4567
25/2 10:00 [19807] - info: NodeBB Ready
25/2 10:01 [19807] - error: TypeError: Cannot call method 'replace' of null
at Object.module.exports.utils.slugify (/opt/projects/nodejs/bbs/public/src/utils.js:78:17)
at Groups.exists (/opt/projects/nodejs/bbs/src/groups.js:441:21)
at /opt/projects/nodejs/bbs/node_modules/async/lib/async.js:656:23
at fn (/opt/projects/nodejs/bbs/node_modules/async/lib/async.js:641:34)
at Object._onImmediate (/opt/projects/nodejs/bbs/node_modules/async/lib/async.js:557:34)
at processImmediate [as _immediateCallback] (timers.js:330:15)
TypeError: Cannot call method 'replace' of null
at Object.module.exports.utils.slugify (/opt/projects/nodejs/bbs/public/src/utils.js:78:17)
at Groups.exists (/opt/projects/nodejs/bbs/src/groups.js:441:21)
at /opt/projects/nodejs/bbs/node_modules/async/lib/async.js:656:23
at fn (/opt/projects/nodejs/bbs/node_modules/async/lib/async.js:641:34)
at Object._onImmediate (/opt/projects/nodejs/bbs/node_modules/async/lib/async.js:557:34)
at processImmediate [as _immediateCallback] (timers.js:330:15)
25/2 10:01 [19807] - info: [app] Shutdown (SIGTERM/SIGINT) Initialised.
25/2 10:01 [19807] - info: [app] Database connection closed.
25/2 10:01 [19807] - info: [app] Web server closed to connections.
25/2 10:01 [19807] - info: [app] Shutdown complete.