Play Framework: Multi Module Project - scala

Question

I have created a multi module project with the following structure:
my_app
|__app
|__conf
|__public
|__project
| |__CommonBuild.scala
|__core
| |__src/main/scala
| |__src/test/scala
| |__build.sbt
|__build.sbt
I notice 2 issues:
In development mode when I do activator run and I make changes to my core module I see that it recompiles but when running it is picking up published core-[ver].jar dependency instead of the module locally.
In IntelliJ IDEA, I see the same issue. Under project structure of my_app I do see core added as both a module and a jar.
CommonBuild.scala:
object CommonBuild {
val settings: Seq[Setting[_]] = Seq(
organization = "com.myorg",
scalaVersion = "2.11.8",
transitiveClassifiers in Global := Seq(Artifact.SourceClassifier),
resolvers ++= Seq(
"scalaz-bintray" at "https://dl.bintray.com/scalaz/releases"
),
aggregate in update := false,
parallelExecution in Test := false,
Keys.fork in Test := false,
libraryDependencies ++= Seq(/*all dependencies here*/)
)
}
core/build.sbt:
name := "core"
CommonBuild.settings
unmanagedResourceDirectories in Compile += baseDirectory.value / "src" / "main" / "resources"
unmanagedResourceDirectories in Test += baseDirectory.value / "src" / "test" / "resources"
publishMavenStyle := true
publishArtifact in Test := true
my_app/build.sbt:
CommonBuild.settings
lazy val my_app =
(project in file(".")).
enablePlugins(PlayScala)
.aggregate(core)
.dependsOn(core % "test->test;compile->compile")
lazy val core = project
name := "my-app"
routesGenerator := InjectedRoutesGenerator
If I do not publish or publishLocal the core artifact, my_app does not pick up the core module to compile and throws a bunch of compilation errors.
How do I make sure that both activator and IntelliJ IDEA use core module itself as the dependency instead of the artifact produced by it?