Add star history to README

README.md

@@ -180,6 +180,8 @@ Measured GPU devices: ['Tesla T4']
 ## Extending **carbontracker**
 See [CONTRIBUTING.md](CONTRIBUTING.md).
 
+## Star History
+[![Star History Chart](https://api.star-history.com/svg?repos=lfwa/carbontracker&type=Date)](https://star-history.com/#lfwa/carbontracker&Date)
 
 ## carbontracker in media
 * Official press release from University of Copenhagen can be obtained here: [en](https://news.ku.dk/all_news/2020/11/students-develop-tool-to-predict-the-carbon-footprint-of-algorithms/) [da](https://nyheder.ku.dk/alle_nyheder/2020/11/studerende-opfinder-vaerktoej-der-forudsiger-algoritmers-co2-aftryk/)