Syncthing an open-source syncing tool.
USE flags for net-p2p/syncthing Open Source Continuous File Synchronization
emerge --ask net-p2p/syncthing
Adding to startup
OpenRC can start Syncthing at startup:
rc-update add syncthing default
If you want to try any path other than /var/lib/syncthing/ which is owned by syncthing user and under syncthing group, you should first change the ownership of the file/folder you've created to syncthing user and group and then add any user you want to have write access to syncthing group. Changes will take place after logging out and in.
usermod -a -G syncthing USERNAME
chmod g+w CREATED_SYNC_FOLDER
chown -R syncthing:syncthing CREATED_SYNC_FOLDER