map = %Q{
  function() {
    emit(this.name, { likes: this.likes });
  }
}

reduce = %Q{
  function(key, values) {
    var result = { likes: 0 };
    values.forEach(function(value) {
      if(value.likes < 0){
          #{Rails.logger.error "likes are negativ" }
      }
      result.likes += value.likes;
    });
    return result;
  }
}

Band.where(:likes.gt => 100).map_reduce(map, reduce).out(inline: true)