Stuck to use sbt-heroku in Skinny Apps

Build.scala.diff

diff --git a/project/Build.scala b/project/Build.scala
index 87a595e..6c5a150 100644
--- a/project/Build.scala
+++ b/project/Build.scala
@@ -8,6 +8,8 @@ import com.earldouglas.xsbtwebplugin.WebPlugin._
 import ScalateKeys._
 import scala.language.postfixOps
 import org.sbtidea.SbtIdeaPlugin._
+import com.heroku.sbt.HerokuPlugin
+import com.typesafe.sbt.SbtNativePackager._

 object SkinnyAppBuild extends Build {

@@ -25,6 +27,8 @@ object SkinnyAppBuild extends Build {
   val jettyVersion = "9.2.1.v20140609" // latest: "9.2.3.v20140905"

   lazy val baseSettings = ScalatraPlugin.scalatraWithJRebel ++ herokuSettings ++ Seq(
+    HerokuPlugin.autoImport.herokuAppName in Compile := "skinny-example",
+    HerokuPlugin.autoImport.herokuProcessTypes in Compile := Map("web" -> "heroku/stage"),
     organization := appOrganization,
     name         := appName,
     version      := appVersion,
@@ -139,15 +143,16 @@ object SkinnyAppBuild extends Build {
       libraryDependencies += "org.skinny-framework" %% "skinny-standalone" % skinnyVersion,
       ideaIgnoreModule := true
     ) ++ jettyOrbitHack
-  )
+  ).enablePlugins(HerokuPlugin)

   // -------------------------------------------------------
   // Deployment on Heroku
   // -------------------------------------------------------
   // Run "./skinny heroku:init"

-  lazy val stage = taskKey[Unit]("Dummy stage task to keep Heroku happy")
-  lazy val herokuSettings = Seq(stage := { "heroku/stage" ! })
+  //lazy val stage = taskKey[Unit]("Dummy stage task to keep Heroku happy")
+  //lazy val herokuSettings = Seq(stage := { "heroku/stage" ! })
+  lazy val herokuSettings = packageArchetype.java_application

 }

console.log

$ sbt build/stage build/deployHeroku 
...

[info] ---> Packaging application...
[info]      - app: skinny-example
java.lang.IndexOutOfBoundsException: 0
	at scala.collection.mutable.ResizableArray$class.apply(ResizableArray.scala:43)
	at scala.collection.mutable.ArrayBuffer.apply(ArrayBuffer.scala:47)
	at com.heroku.sbt.Deploy$.buildUniversalSlug(Deploy.scala:177)
	at com.heroku.sbt.Deploy$.buildSlug(Deploy.scala:148)
	at com.heroku.sbt.Deploy$.apply(Deploy.scala:73)
	at com.heroku.sbt.DeployBuilder.deploy(Deploy.scala:49)
	at com.heroku.sbt.HerokuPlugin$autoImport$$anonfun$baseHerokuSettings$1.apply(HerokuPlugin.scala:33)
	at com.heroku.sbt.HerokuPlugin$autoImport$$anonfun$baseHerokuSettings$1.apply(HerokuPlugin.scala:19)
	at scala.Function1$$anonfun$compose$1.apply(Function1.scala:47)
	at sbt.$tilde$greater$$anonfun$$u2219$1.apply(TypeFunctions.scala:40)
	at sbt.std.Transform$$anon$4.work(System.scala:63)
	at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:226)
	at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:226)
	at sbt.ErrorHandling$.wideConvert(ErrorHandling.scala:17)
	at sbt.Execute.work(Execute.scala:235)
	at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:226)
	at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:226)
	at sbt.ConcurrentRestrictions$$anon$4$$anonfun$1.apply(ConcurrentRestrictions.scala:159)
	at sbt.CompletionService$$anon$2.call(CompletionService.scala:28)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:744)
[error] (build/compile:deployHeroku) java.lang.IndexOutOfBoundsException: 0
[error] Total time: 85 s, completed Oct 13, 2014 5:21:13 PM