Unifi-7.5 release doesnt seem to support arm so I held the version at 7.4.
[Unit]
Description=WriteFreely %I Instance
After=syslog.target network.target
[Service]
WorkingDirectory={{writefreely_dir}}/%i/
ExecStart=/usr/local/bin/writefreely
Restart=always
User={{writefreely_user}}
[Install]
WantedBy=multi-user.target