added readme

examples/evaluation/ragas/ragas_readme.md

@@ -1,6 +1,6 @@
 ## Ragas x Open AI
 
-- [Ragas evaluation]()
-- [Ragas synthetic test data generation]()
+- [Ragas evaluation](https://github.com/openai/openai-cookbook/examples/evaluation/ragas/openai-ragas-eval-cookbook.ipynb)
+- [Ragas synthetic test data generation](https://github.com/openai/openai-cookbook/examples/evaluation/ragas/openai-ragas-synthetic-test.ipynb)
 
 For more information on Ragas, refer to the [Ragas documentation](https://ragas.readthedocs.io/en/latest/)