doc: update readme with example (#145)

* doc: update readme with example

We have the wiki but it is not easily findable

* Update README.md

Author: smyrick

README.md

@@ -93,3 +93,11 @@ type Widget {
 ## Documentation
 
 There are more examples and documention in our [Wiki](https://github.com/ExpediaDotCom/graphql-kotlin/wiki) or you can view the [javadocs](https://www.javadoc.io/doc/com.expedia/graphql-kotlin) for all published versions
+
+If you have a question about something you can not find in our wiki or javadocs, feel free to [create an issue](https://github.com/ExpediaDotCom/graphql-kotlin/issues) and tag it with the question label.
+
+## 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.
+
+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).