Update README.md

Author: kasramp

README.md

@@ -46,6 +46,9 @@ Once everything is up and running open the browser and go to [http://localhost:8
 
 The integration tests written relying on [testcontainers](https://www.testcontainers.org/) to spin up Elasticsearch on the spot to run tests against.
 
+To know more about container read this tutorial:
+[https://blog.madadipouya.com/2019/05/08/integration-test-with-testcontainers-in-java/](https://blog.madadipouya.com/2019/05/08/integration-test-with-testcontainers-in-java/)
+
 To run them just execute below command:
 
 ```bash