Enable Gradle debugging for scala play throws Exiting continuous build as Gradle did not detect any file system inputs

Question

I am using gradle (./gradlew) with scala play. In order to launch my app I use the following: ./gradlew run

Now I want to create a command to run app in debug mode in IntelliJ:

task debugPlayBinary {
    doLast {
        def runPlayTask = tasks.findByName('runPlay')
        runPlayTask.forkOptions.jvmArgs = ['-Xdebug', '-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005']
        runPlayTask.run()
    }
}

However when I run ./gradlew debugPlayBinary I get:

Exiting continuous build as Gradle did not detect any file system inputs.
[info] p.c.s.AkkaHttpServer - Stopping Akka HTTP server...
[info] p.c.s.AkkaHttpServer - Terminating server binding for /0:0:0:0:0:0:0:0:9000
[info] p.c.s.AkkaHttpServer - Running provided shutdown stop hooks

Can someone help me understand what's going wrong here?