Gradle runtime dependecies not resolved

I have set up an grails 3 application using Intellij IDEA EAP 15.

Now adding the mysql connector to my build.gradle and running the app inside Intellij gives me an ClassNotFoundException.

buildscript {
   ext {
      grailsVersion = project.grailsVersion
   }
   repositories {
      mavenLocal()
      maven { url "https://repo.grails.org/grails/core" }
   }
   dependencies {
      classpath "org.grails:grails-gradle-plugin:$grailsVersion"
      classpath "com.bertramlabs.plugins:asset-pipeline-gradle:2.5.0"
      classpath "org.grails.plugins:hibernate:4.3.10.5"
   }
}

plugins {
   id "io.spring.dependency-management" version "0.5.2.RELEASE"
}

version "0.1"
group "nexttext"

apply plugin: "spring-boot"
apply plugin: "war"
apply plugin: "asset-pipeline"
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: "org.grails.grails-web"
apply plugin: "org.grails.grails-gsp"

ext {
   grailsVersion = project.grailsVersion
   gradleWrapperVersion = project.gradleWrapperVersion
}

assets {
   minifyJs = true
   minifyCss = true
}

repositories {
   mavenLocal()
   maven { url "https://repo.grails.org/grails/core" }
}

dependencyManagement {
   imports {
      mavenBom "org.grails:grails-bom:$grailsVersion"
   }
   applyMavenExclusions false
}

dependencies {
   compile "org.springframework.boot:spring-boot-starter-logging"
   compile "org.springframework.boot:spring-boot-starter-actuator"
   compile "org.springframework.boot:spring-boot-autoconfigure"
   compile "org.springframework.boot:spring-boot-starter-tomcat"
   compile "org.grails:grails-dependencies"
   compile "org.grails:grails-web-boot"

   compile "org.grails.plugins:hibernate"
   compile "org.grails.plugins:cache"
   compile "org.hibernate:hibernate-ehcache"
   compile "org.grails.plugins:scaffolding"

   runtime "org.grails.plugins:asset-pipeline"
   runtime "mysql:mysql-connector-java:5.1.37"
   
   testCompile "org.grails:grails-plugin-testing"
   testCompile "org.grails.plugins:geb"

   // Note: It is recommended to update to a more robust driver (Chrome, Firefox etc.)
   testRuntime 'org.seleniumhq.selenium:selenium-htmlunit-driver:2.44.0'

   console "org.grails:grails-console"
}

task wrapper(type: Wrapper) {
   gradleVersion = gradleWrapperVersion
}

Running my application via "grails run-app" from the commandline is working.

Any suggestions?