add gretty plugin to run the app from command line

Author: k4ml

tutorials/servlet-web-applications/README.md

@@ -1 +1,11 @@
 Code for the [Creating Web Applications with Http Servlets](http://kotlinlang.org/docs/tutorials/httpservlets.html) tutorial.
+
+To run this from command line, we can use [gretty], a gradle plugin to run the application war under Jetty.
+
+Run this command to start the app:-
+
+    gradle appStart
+
+References - https://www.petrikainulainen.net/programming/gradle/getting-started-with-gradle-creating-a-web-application-project/
+
+[gretty]:https://github.com/akhikhl/gretty/blob/master/changes.md

tutorials/servlet-web-applications/build.gradle

@@ -5,11 +5,13 @@ buildscript {
     }
     dependencies {
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+        classpath 'org.akhikhl.gretty:gretty:+'
     }
 }
 
 apply plugin: 'kotlin'
 apply plugin: 'war'
+apply plugin: 'org.akhikhl.gretty'
 
 repositories {
     jcenter()
@@ -31,4 +33,9 @@ sourceSets {
             srcDir "test/main/kotlin"
         }
     }
-}
+}
+
+gretty {
+    contextPath = '/'
+    servletContainer = 'jetty9'
+}