add autoaupdater, update readme

autoupdater using systemd timer and service.

autoupdater/tetosong.timer

@@ -0,0 +1,10 @@
+[Unit]
+Description=Run tetosong service once a week
+
+[Timer]
+OnCalendar=Sun *-*-* 05:00:00
+Persistent=true
+Unit=tetosong.service
+
+[Install]
+WantedBy=timers.target