Peter I contacted the developer with the same concern and he told me that it does not have any license but I'm free to use and fork it however I want and encourage me to do it.
Modanung What's GNU Taler?
Donate buttons is easy to implement, the rating system maybe more complicated but I like the idea.
poVoq it is too late to discourage me because the work is done, what's left is adding more games and features. I like contentDB but I'm not attempting to copy it or any other similar database, they are all great and unique in their own way, mine will be different: I'm not going to host any game, that would be expensive and complicated and it is out of my plans.
For now I will be adding games and maybe some extra filters but in order to make sense of adding more features and spending much time on it I need to find an apropiate hosting first because the current one has a lot of limitations and make deploying and testing time consuming.
Thanks for the feedback, feel free to fork it and submit your own implementations of any of the features mentioned above!