gistfile1.rb

 def self.parent_select_options
    options = [['-- No Parent --', nil]]
    Tag.recurse_for_parent_select_options(Tag.roots,options)
    return options
  end

  def self.recurse_for_parent_select_options(nodes,options)
    nodes.each do |node|
      prefix = node.depth > 0 ? ' -' * node.depth + ' ' : ''
      options << [ prefix + node.title, node.id]
      Tag.recurse_for_parent_select_options(node.children,options)
    end
  end