How do I modify Rails ActiveRecord query results before returning?
MyModel.some_custom_scope.some_other_scope.enhance_with_external_data.each do |object|
  puts object.some_attribute_from_external_data_source
end

def self.enhance_with_external_data
  external_data = get_external_data
  Enumerator.new do |yielder|
    # mimick some stuff I saw in ActiveRecord and don't quite understand:
    relation.to_a.each do |obj|
      update_obj_with_external_data(obj)
      yielder.yield(obj)
    end
  end
end

MyModel.some_custom_scope.some_other_scope.enhance_with_external_data

def self.merge_with_extra_info
  the_scope = scoped
  class << the_scope
    alias :base_to_a :to_a
    def to_a
      MyModel.enhance(base_to_a)
    end
  end
  the_scope
end

def self.enhance(items)
  items.each do |item|
    item = add_extra_item_info(item)
  end
  items
end

MyModel.where(:some_attribute => some_value).merge_with_extra_info.limit(10).all