title: How to model this rails relationship, "has two"?
body: <p>Imagine a roster of characters in a game.</p>
  
  <p>I need to let users vote on which character counters which character and be able to save that in the database.</p>
  
  <p><code>Batman is strong against Superman</code></p>
  
  <p><code>Batman is strong against Joker</code></p>
  
  <p><code>Batman is weak against The Riddler</code></p>
  
  <hr>
  
  <p>How can I model this relationship between two of the same type of models? <code>Batman, Superman and Joker</code> are all part of the same Model type <code>Superhero</code>. </p>
  
  <p>If I were to create this same system on something like ASP.Net MVC, I would create a table called <code>Counterpicks</code> and have two fields <code>source_id</code> and <code>target_id</code> as int fields and use them as foreign keys towards the <code>Superhero</code> table. Do I need to create a <code>Counterpick</code> model in RoR?</p>
  
  <p>Any suggestions?</p>