Add Grails sample app

Closes gh-250

samples/rest-notes-grails/grails-app/init/com/example/Application.groovy

@@ -0,0 +1,10 @@
+package com.example
+
+import grails.boot.GrailsApp
+import grails.boot.config.GrailsAutoConfiguration
+
+class Application extends GrailsAutoConfiguration {
+    static void main(String[] args) {
+        GrailsApp.run(Application, args)
+    }
+}