You just imported the SBT project of Activator or Play framework app in IntelliJ IDEA (14), and you found that you "routes" among other symbols do not resolve.
You are lacking the dependency for the auto-generated routing class.
You can add Module Dependency to classes_managed. This is located in the target/scala_2
I originally posted a similar solution, but this one is much better and works with Play 2.3 or later. This video shows you exactly what you will need to do.