I thought that building a translation tool on top of Github (at the moment) would eliminate the hassle of syncing the keys between the service and your repository.
Babelfu is in a pretty alpha stage, with minimal features to test the idea, but it's enough to get a taste of its potential. If you want to give it a try, you can follow this guide https://github.com/babelfu/babelfu-demo
There is an instance ready for use at https://babelfu.com
If you are interested in the idea or have any feedback, use the GitHub issues, email me (check my profile), or use this thread.
Many thanks for your time!