more details about demo account

doc/fai-guide.txt

@@ -7,7 +7,7 @@ FAI Guide (Fully Automatic Installation)
 Thomas Lange <lange@informatik.uni-koeln.de>
 Mon, 21 Sep 2017
 :Date: a date
-:Revision: 5.4
+:Revision: 5.5
 
 :nfsrootsize: 780
 :mirrorsize: 56
@@ -1407,7 +1407,7 @@ types (shell, cfengine, ...) to be executed for one class.
 
 The default set of scripts in '$FAI/scripts' include examples for
 installing Debian and CentOS machines. They set the root password, add
-a demo user account, set the timezone, configure the network for DHCP
+a user account (set by '$username, default to demo), set the timezone, configure the network for DHCP
 or using a fixed IP address, setup grub and more.
 They should do a reasonable job for your installation. You can edit
 them or add new scripts to match your local needs.