title: convert from a 2d array to nested_set in Ruby on rails
body: <p>I have a tree structure in a .csv file (nodes are of type text), and after reading the csv i want to store the data in a ruby object. I went through a few tree plugins and i think nested_set would serve the purpose for me.
  However, i am facing problem with fixing a format of csv file, so that i can read it and convert into tree object. Is there any direct way of converting a csv file or 2 dimensional array, into a tree data structure??</p>