There are no rules. The devs just got those coins prior to launching the coin and from there on said that whoever with a reddit Account would be able to get 1 coin. This hasn't completed yet, as the devs aren't looking to be moving forward with that. The subreddit has an old post about that. You'd have to put your Reddit username on https://garlicoinairdrop.com/ if you'd want to try regardless, but it seems like they've closed that website as well.