code: def tree
        @tree and return @tree 
        @tree = []
        file_set = version_files
  
        while child = file_set.shift
          tree << child #if child.dir?
  
          if child.type == "dir"
            file_set.unshift( github.where(child.path).contents ).flatten!
          end
        end
  
        @tree
      end
docs: build a depth first tree