title: Arel complex query
body: <p>So i have the following tables</p>
  
  <pre><code>class Game
    belongs_to :player0, :class =&gt; "Player"
    belongs_to :player1, :class =&gt; "Player"
  end
  
  class Player
    belongs_to :user
  end
  
  
  class User
    #has a field called race
  end
  </code></pre>
  
  <p>Now i need a query to do the following</p>
  
  <p>Find all Games where player0.user.race is "x" and player1.user.race is "y" OR player0.user.race is "y" and player1.user.race is "x".</p>
  
  <p>I just began using rails 3. I can easily write the query myself in sql, but i'd rather learn the arel way.</p>