docs: update example app information in README (ExpediaGroup#193)

Author: dariuszkuc

README.md

@@ -98,6 +98,6 @@ If you have a question about something you can not find in our wiki or javadocs,
 
 ## Example
 
-One way to run a GraphQL server is with Spring Boot. A sample Spring Boot app that uses `graphql-kotlin`, [graphql-java-servlet](https://github.com/graphql-java-kickstart/graphql-java-servlet) and [graphiql](https://github.com/graphql/graphiql) is provided in the [example folder](https://github.com/ExpediaDotCom/graphql-kotlin/tree/master/example). All the examples used in this documentation should be available in the sample app.
+One way to run a GraphQL server is with Spring Boot. A sample Spring Boot app that uses [Spring Webflux](https://docs.spring.io/spring/docs/current/spring-framework-reference/web-reactive.html) together with `graphql-kotlin` and [graphql-playground](https://github.com/prisma/graphql-playground) is provided in the [example folder](https://github.com/ExpediaDotCom/graphql-kotlin/tree/master/example). All the examples used in this documentation should be available in the sample app.
 
-In order to run it you can run [Application.kt](https://github.com/ExpediaDotCom/graphql-kotlin/blob/master/example/src/main/kotlin/com.expedia.graphql.sample/Application.kt) directly from your IDE. Alternatively you can also use the Spring Boot maven plugin by running `mvn spring-boot:run` from the command line. Once the app has started you can explore the example schema by opening GraphiQL endpoint at [http://localhost:8080/graphiql](http://localhost:8080/graphiql).
+In order to run it you can run [Application.kt](https://github.com/ExpediaDotCom/graphql-kotlin/blob/master/example/src/main/kotlin/com.expedia.graphql.sample/Application.kt) directly from your IDE. Alternatively you can also use the Spring Boot maven plugin by running `mvn spring-boot:run` from the command line. Once the app has started you can explore the example schema by opening GraphiQL endpoint at [http://localhost:8080/playground](http://localhost:8080/playground).