efdenny's suggestion is a perfectly good method. Just be clear that it's not a "sync". If, for example, you make a change to a player's name in the database on PC 1, and then use the backup/restore method to move data from PC 2 to PC 1, you're going to lose the aforementioned change.
Another method is to simply pass the saved tournament files back and forth. Let's say you started everything on PC 1. You've added your 10 players to the database, and you run your first tournament. The next game is at the other location, so their TD doesn't have anybody in the database yet and no saved tournaments. Send the saved tournament file for tournament 1 over to the other location. Load up the tournament. On the Players tab, press the Database button, and then press the "Add to the database players in your current tournament" button and add all the players to your database. You're now synced. All players are in both databases, and the saved tournament is also on both PCs.
Anytime you run a tournament, send the saved tournament file to the other location and repeat the above steps.
What this method won't get are player information changes. For example, if you give someone already in the database a new nickname. That change won't get synced using this method. But this only applies to player personal information (name, address, phone, etc) and league and season information and membership.