Example systemd service unit file

This adds a systemd service unit file for managing the FixMyStreet
Catalyst process manager.

This also updates the commonlib submodule with matching changes to
our install scripts.

CHANGELOG.md

@@ -29,6 +29,7 @@
         - Move away from FastCGI in sample conf/sysvinit config.
         - Customised Vagrant box available, with an override option.
         - Add Dockerfile and example Docker Compose setup.
+        - Add a sample systemd unit file for the Catalyst application server.
 
 * v2.4 (6th September 2018)
     - Security

conf/systemd.example

@@ -0,0 +1,21 @@
+[Unit]
+Description=FixMyStreet Catalyst Application Server
+Documentation=https://fixmystreet.org/
+After=network.target
+
+[Service]
+Type=forking
+User=fms
+PIDFile=/var/www/fixmystreet/fixmystreet.pid
+ExecStartPre=mkdir /var/www/fixmystreet/logs
+ExecStart=/var/www/fixmystreet/fixmystreet/script/server \
+            --port 9000 \
+            --env deployment \
+            --daemonize \
+            --pid /var/www/fixmystreet/fixmystreet.pid \
+            --access-log /var/www/fixmystreet/logs/fixmystreet.access.log \
+            --error-log /var/www/fixmystreet/logs/fixmystreet.error.log
+ExecStop=kill -TERM $MAINPID
+
+[Install]
+WantedBy=multi-user.target