[Guide] PairDrop - change port

[Denny-89]

It's really easy:

1. Open /etc/systemd/system/pairdrop.service with any text editor, e.g. nano /etc/systemd/system/pairdrop.service
2. Add Environment=PORT=80 (replace 80 with the desired port) in the [Service] section, save and exit.
3. Run systemctl daemon-reload and then systemctl restart pairdrop or just reboot the PairDrop LXC.

In case if you accidentally removed anything - here's how my edited service file looks like:

[Unit]
Description=PairDrop Service
After=network.target

[Service]
ExecStart=npm start
WorkingDirectory=/opt/pairdrop
Environment=PORT=80
Restart=always

[Install]
WantedBy=multi-user.target