Latter if you need a cards data auto update (who knows when Bilzzard will release a hotfix and diminish some cards), there's a database auto update script auto_update.py, add it to system autostart tasks, and then for every 6 hours (you may change it to any interval by modifying the scrpit).

On a Ubuntu 18+, you may do so:

Create unit file in /lib/systemd/system/hearthstone_deck_auto_update.service with the following content:

[Unit]
Description=<hearthstone_deck_auto_update>
After=network.target network-online.target

[Service]
Type=simple
User=<required_user_name>
Group=<required_group_name>
Restart=always
ExecStartPre=/bin/mkdir -p /var/run/hearthstone_deck_auto_update
PIDFile=/var/run/hearthstone_deck_auto_update/service.pid
ExecStart=/path/to/your/auto_update.py

[Install]
WantedBy=multi-user.target

Save this file and reload systemd:

sudo systemctl daemon-reload

Then add your service to autostart:

sudo systemctl enable hearthstone_deck_auto_update.service

you should see that Systemd created required symlinks after enable action.

Reboot and see if it's up and running (ps aux | grep python or sudo systemctl status hearthstone_deck_auto_update.service). If there is something weird - check Systemd journal:

sudo journalctl -xe