decrease user count when user is deleted

src/user/delete.js

@@ -293,6 +293,9 @@ module.exports = function(User) {
 					},
 					function(next) {
 						db.delete('user:' + uid, next);
+					},
+					function(next) {
+						db.decrObjectField('global', 'userCount');
 					}
 				], callback);
 			});