add an example systemd service

Author: xtaci

examples/kcptun.service

@@ -0,0 +1,16 @@
+Description=kcptun
+
+Wants=network.target
+After=syslog.target network-online.target
+
+[Service]
+Type=simple
+Environment=GOGC=20
+ExecStart=/home/user/client_linux_amd64 -c /home/user/local.json
+Restart=on-failure
+RestartSec=10
+KillMode=process
+LimitNOFILE=65536
+
+[Install]
+WantedBy=multi-user.target