Make app (re)Start Automatically and restart on failure (systemd)

useradd isso
nano /etc/systemd/system/service.service

put:

[Unit]
Description=lightweight Disqus alternative

[Service]
User=isso
Environment="ISSO_SETTINGS=/etc/isso.conf"
ExecStart=/usr/bin/gunicorn --log-file /var/log/isso.log --preload isso.run
Restart=always

[Install]
WantedBy=multi-user.target

then:

sudo systemctl enable service.service