VanillaGradle doesn't have genIntellijRuns

Interestingly, there are three versions of the vanillagradle plugin: Gradle - Plugins

The docs say I should use the server version. That explains why there are no run tasks.
I have switched to the merged version -> there is genIntellijRuns. It created the run configurations. Both(server and client) have a red cross showing “GradleStartServer is not in this module”. Running this config results in “main class not found”. There aren’t any files in the run folder.

Running the runServer gradle task results in MISSING REPLACEMENT DATA FOR RUN_CLIENT_MAIN.

minecraft {
    version = "1.11.2"
    mappings = "snapshot_20170529"
    runDir = "run"
}

Am I doing it right with the merged version instead of the server one?