Add running instruction to readme file

Author: kasramp

README.md

@@ -1,3 +1,24 @@
 # Spring Kafka test example
 
-Spring Kafka with unit test example
+Spring Kafka with unit test example.
+
+## How to run
+
+First start the docker-compose which contains ZooKeeper, Kafka, and Kafdrop.
+
+```bash
+$ docker-compose -f docker-compose.yml up -d
+```
+
+Once all the containers are healthy start the application,
+
+```bash
+$ ./mvnw spring-boot:run
+```
+
+Open the browser `localhost:8080/apidocs`. 
+
+You can interact with the `random` api to create a random user which then will be sent to Kafka and consumed by the consumer (see `consumer/UserKafkaListener.java` file).
+
+To see whether the message has been sent to Kafka, open your browser `http://localhost:8085/topic/com.madadipouya.kafka.use` (Kafdrop environment), 
+you should be able to see all messages that sent to `kafka.user` topic.