Play Scala sbt-concat: grouping order

Question

I have a problem with the sbt-concat plugin that I use to group my entire JS file into assets / javascripts. The problem is that it is not grouped in the correct order.

Basically, my tree looks like this:

-assets
--javascripts
---dashboard
----controller.js
---app.js

And the created file, thanks to sbt-concat, loads controller.js in front of app.js, which obviously cause the controller to crash.

Here is my plugin.sbt:

addSbtPlugin("com.typesafe.sbt" % "sbt-digest" % "1.1.0")

addSbtPlugin("com.typesafe.sbt" % "sbt-gzip" % "1.0.0")

addSbtPlugin("com.typesafe.sbt" % "sbt-uglify" % "1.0.3")

addSbtPlugin("net.ground5hark.sbt" % "sbt-concat" % "0.1.8")

and my build.sbt:

Concat.groups := Seq(
    "scripts.js" -> group(((sourceDirectory in Assets).value / "javascripts") ** "*.js")
)

Concat.parentDir := "javascripts"

includeFilter in uglify := GlobFilter("scripts.js")

pipelineStages in Assets := Seq(concat, uglify, digest, gzip)

So everything works fine, except that app.js does not load at first, this is the only thing I need to download first, if any of you have an idea just for that, that would be awesome! Thanks: D