Add example systemd unit files for prune job

0x0-prune.service

@@ -0,0 +1,22 @@
+[Unit]
+Description=Prune 0x0 files
+After=remote-fs.target
+
+[Service]
+Type=oneshot
+User=nullptr
+WorkingDirectory=/path/to/0x0
+BindPaths=/path/to/0x0
+
+Environment=FLASK_APP=fhost
+ExecStart=/usr/bin/flask prune
+ProtectProc=noaccess
+ProtectSystem=strict
+ProtectHome=tmpfs
+PrivateTmp=true
+PrivateUsers=true
+ProtectKernelLogs=true
+LockPersonality=true
+
+[Install]
+WantedBy=multi-user.target

0x0-prune.timer

@@ -0,0 +1,9 @@
+[Unit]
+Description=Prune 0x0 files
+
+[Timer]
+OnCalendar=hourly
+Persistent=true
+
+[Install]
+WantedBy=timers.target

README.rst

@@ -35,8 +35,14 @@ downsides, one of them being that range requests will not work. This is a
 problem for example when streaming media files: It won’t be possible to seek,
 and some ISOBMFF (MP4) files will not play at all.
 
-To make files expire, simply create a cronjob that runs ``FLASK_APP=fhost
+To make files expire, simply run ``FLASK_APP=fhost flask prune`` every
-flask prune`` every now and then.
+now and then. You can use the provided systemd unit files for this::
+
+    0x0-prune.service
+    0x0-prune.timer
+
+Make sure to edit them to match your system configuration. In particular,
+set the user and paths in ``0x0-prune.service``.
 
 Before running the service for the first time, run ``FLASK_APP=fhost flask db upgrade``.