How to serve a SCSS processed file in a subproject with sbt-sassify?

[cyrilfr]

I'm writing an app composed of several subprojects:

app
++ controllers
conf
common
++ app
+++ assets
++++ stylesheets
+++++ pdf.scss
+++ controllers
+++ models
+++ views
++++ pdf.scala.html
++ conf
+++ common.routes
+++ common.conf

In the common subproject, I have SCSS files that I want to use in a view in the same subproject. In the controllers packages, I added a file in order to be able to serve assets:

package controllers.common;

import controllers.AssetsMetadata;
import play.api.http.HttpErrorHandler;
import play.api.mvc.Action;
import play.api.mvc.AnyContent;

import javax.inject.Inject;

public class Assets extends controllers.Assets {

    @Inject
    public Assets(
        HttpErrorHandler errorHandler,
        AssetsMetadata meta
    ) {
        super(errorHandler, meta);
    }

    public Action<AnyContent> versioned(String path, controllers.Assets.Asset file) {
        return super.versioned(path, file);
    }
}

with a line in the common.routes file:

GET /assets/*file controllers.common.Assets.versioned(path="/public", file: Asset)

and routes:

-> /common common.Routes

but when I try to access a CSS file localhost:9000/common/assets/stylesheets/pdf.css, I get an error: Action Not Found