update systemd

systemd/tunasync-snapshot-gc.service

@@ -0,0 +1,11 @@
+[Unit]
+Description=Delete garbage subvolumes generated by tunasync
+Requires = network.target
+After = network.target
+
+[Service]
+Type=simple
+ExecStart=/home/tuna/.virtualenvs/tunasync/bin/python -u /home/tuna/tunasync/tunasync_snapshot_gc.py -c /etc/tunasync.ini
+
+[Install]
+WantedBy = multi-user.target