gradle: migrate spring app to a multiproject build

I followed this tutorial. This runs fine. I would like to create a multiproject build with one project that contains this spring application. So I added this project to a subfolder called web of this multiproject build, added a settings.gradle file:

include 'web'

As well as a build.gradle file:

apply plugin: 'application'
mainClassName = "hello.Application"

jar {
  baseName = 'VoPro'
}

dependencies {
  compile project(':web')
}

However, when i run $ gradle build, i get the error:

Could not resolve all dependencies for configuration ':runtime'.
> Cannot resolve external dependency org.springframework.boot:spring-boot-starter-web: because no repositories are defined.
  Required by:
      :test:unspecified > test:web:unspecified

Why can't gradle find any repositories?