docs: function initServices (config) {
      // get services directory
      var dirs = getDir(config, 'services')
      // load services definitions from each directory
      _.each(dirs, dir => initServicesDir(config, dir))
      // create new service instances from definitions
      _.each(config.services, (service, name) => {
          config.services[name] = new ImmutableCoreService(service)
      })
      // initialize all services
      return ImmutableCoreService.initializeAll()
  }