title: Database scheme for tree comments
body: <p>What is the best way to implement tree comments (each comment can have comments, those comments can have comments too).
  It should be up to 10 levels of comments.</p>
  
  <p>I'm using Rails with PostgreSQL database.</p>
  
  <p>The obvious way is to do this like</p>
  
  <pre><code>has_many :comments
  belongs_to :comment
  </code></pre>
  
  <p>But I assume there is a better way to do it.</p>