Warning: steam have limit of ~250 invites per (hour, two hours, day, week, ???), per community group.

Warning: you'll need to create steam account for inviter and spend at least $5 on the Steam store.

Warning: sending automated group invites is a violation of the Steam Subscriber Agreement.

1. Install requirements pip2 install -r requirements.txt
2. Configure cp inviter.conf.example inviter.conf
3. Run ./inviter.py
4. Cron it to run daily

Check https://steamcommunity.com/groups/{your_group_abbreviation}/history (it may update with some delay)