How to embed a Mongoid tree in another document?

I'm using mongoid-tree but this question probably applies to other acts_as_tree ports for Mongoid.

I want a tree of nodes and I want the whole tree to be embedded in another document. My problem is that this really only requires that 开发者_C百科the root node be embedded but all nodes have the same embedded_in. In my case:

class Container
  include Mongoid::Document

  embeds_one :root, :class_name => "Node"
end

class Node
  include Mongoid::Document
  include Mongoid::Tree

  embedded_in :container, :inverse_of => :root
end

How can I set this up so that only one record per tree is embedded_in the Container? Is there another approach that would be better?

The author of mongoid-tree, benedikt, answered on GitHub.

Currently Mongoid::Tree doesn't work with embedded Nodes. He suggests:

class Container
  include Mongoid::Document

  referenced_in :node, :inverse_of => :container
end

class Node
  include Mongoid::Document
  include Mongoid::Tree

  references_one :container
end

This way you any node can be assigned to a container. You could also overwrite the Node.container method to call root.container for child nodes so you'd get the container for subnodes as well.