Add reference to the #espresso Slack channel.

espresso-jshell/README.md

@@ -3,7 +3,9 @@
 This demo showcases the integration between [GraalVM Native Image](https://www.graalvm.org/reference-manual/native-image/) and [Java-on-Truffle (Espresso)](https://www.graalvm.org/reference-manual/java-on-truffle/).  
 It builds a native image of `jshell`, that executes the dynamically generated bytecodes on Espresso. This hybrid mode achieves instant startup, beating the vanilla `jshell` in both: time to the first interaction and time to evaluate a simple expression.
 
-JShell is a Java read-eval-print loop tool first introduced in Java 9, this demo also allows to run `jshell` on Java 8.
+JShell is a Java read-eval-print loop tool first introduced in Java 9, this demo also allows to run `jshell` on Java 8.  
+For further discussions and questions please join our `#espresso` channel on the [GraalVM Slack Community](https://graalvm.slack.com/).
+
 
 ## Prerequisites