added star history to readme.md

README.md

@@ -28,6 +28,10 @@ Find a live version of the latest explorer UI: [https://eclipse.github.io/ditto/
 
 You should be able to work with your locally running default using the `local_ditto` environment - and you can add additional environments to also work with e.g. with a deployed installation of Ditto.
 
+## Star History
+
+[![Star History Chart](https://api.star-history.com/svg?repos=eclipse/ditto&type=Date)](https://star-history.com/?secret=Z2hwXzJERUNBUmFRa09KM3BvdTFMUkJ1Y3VnY25FV3hxVjNBM3hEVQ==#eclipse/ditto&Date)
+
 ## Getting started
 
 In order to start up Ditto via *Docker Compose*, you'll need: