Merge branch 'master' into 'master'

Small documentation update, add unixsocketperm

If you run gitlab as user ``git`` while redis runs as user ``redis`` and you add git to ``redis`` group, you'll need to set ``unixsocketperm = 0775`` to grant write access to group.

See merge request !192

doc/update/7.2-to-7.3.md

@@ -72,6 +72,8 @@ sudo cp lib/support/init.d/gitlab /etc/init.d/gitlab
     sed 's/^port .*/port 0/' /etc/redis/redis.conf.orig | sudo tee /etc/redis/redis.conf
     # Enable Redis socket for default Debian / Ubuntu path
     echo 'unixsocket /var/run/redis/redis.sock' | sudo tee -a /etc/redis/redis.conf
+    # Be sure redis group can write to the socket, enable only if supported (>= redis 2.4.0).
+    sed -i '/# unixsocketperm/ s/^# unixsocketperm.*/unixsocketperm 0775/' /etc/redis/redis.conf
     # Activate the changes to redis.conf
     sudo service redis-server restart
     # Add git to the redis group