add systemd info, clean up Support section

README.pod

@@ -40,6 +40,62 @@ To use a custom configuration file, the C<-c config> parameter is supported;
 note that using this option will not read the global or local configuration
 files and only use the variables from this custom file.
 
+=head1 SYSTEMD
+
+The provided systemd unit files are designed to use the native systemd timer
+functionality in place of a cron daemon. The timer can be activated as the
+system user which will use specifically the global F</etc/petrified.conf> 
+configuration, or as any given user which will use the F<~/.petrifiedrc>
+configuration.
+
+ system: systemctl --now enable petrified.timer
+         systemctl list-timers petrified.timer
+
+ user:   systemctl --user --now enable petrified.timer
+         systemctl --user list-timers petrified.timer
+
+A target of C<petrified.target> is pre-configured if multuple interfaces are
+to be configured; per standard systemd methodology the existing service unit
+is first customized either at the system or user level, then all custom units
+and the timer are started/enabled.
+
+For example at the system level if two interfaces are to be used, it might
+look like:
+
+ /etc/systemd/system/petrified-iface1.service
+ --------------------------------------------
+ .include /usr/lib/systemd/system/petrified.service
+ [Service]
+ ExecStart=/usr/bin/petrified -c /etc/petrified-iface1.conf
+
+ /etc/systemd/system/petrified-iface2.service
+ --------------------------------------------
+ .include /usr/lib/systemd/system/petrified.service
+ [Service]
+ ExecStart=/usr/bin/petrified -c /etc/petrified-iface2.conf
+
+Then both customized service units are enabled, as well as the timer unit:
+
+ systemctl --now enable petrified-iface1.service
+ systemctl --now enable petrified-iface2.service
+ systemctl --now enable petrified.timer
+
+The per user configuration looks the same and is usually configured in the
+F<~/.config/systemd/user/> space in the home directory. The provided units
+for the service contain the connection to the target pre-configured.
+
+=over 4
+
+=item B<See also:>
+
+L<http://www.freedesktop.org/software/systemd/man/systemd.unit.html>
+
+L<http://www.freedesktop.org/software/systemd/man/systemd.timer.html>
+
+L<http://www.freedesktop.org/software/systemd/man/systemd.target.html>
+
+=back
+
 =head1 DEPENDENCIES
 
  Utilities                          | Package
@@ -82,10 +138,10 @@ Copyright (c) 2015 Troy Engel
 
 GPLv3 - see LICENSE for details
 
-L<https://github.com/troyengel/petrified>
-
 =head2 SUPPORT
 
 If you like this software, please consider upgrading to a Premium account
-to help support the L<Free DNS|http://freedns.afraid.org> project.
+to help support the L<Free DNS|http://freedns.afraid.org> project. All
+questions and issues should be asked/reported via the Github project:
 
+L<https://github.com/troyengel/petrified>