Show HN: I built an app to track what countries you visited

As an avid traveler and player of "map painting games" like Crusader Kings or Europa Universalis, I always wanted to paint the world map with my travels.

This small app lets you track and visualize what countries you have already visited. Hopefully it brings a smile to your face once you complete your map!

It's also open-source: https://github.com/exler/placemarker

What do you think?