title: Preloading deeply nested associations in Ecto
body: <p>It's clear how to preload associations in Ecto 1-2 levels deep, such as post and comments to it. </p>
  
  <p>I have an <code>Address</code>, and <code>Address</code> <strong>belongs_to</strong> a <code>Street</code>, and  <code>Street</code> <strong>belongs_to</strong> a <code>City</code>, and <code>City</code> <strong>belongs_to</strong> Region, and <code>Region</code> <strong>belong_to</strong> a <code>Country</code></p>
  
  <p>Given <code>Address</code>:</p>
  
  <pre><code>addr = Repo.get(Address, 123)
  |&gt; Repo.preload(street: ?????)
  </code></pre>
  
  <p>how do I preload it all the way to <code>Country</code>:</p>
  
  <pre><code>IO.puts("the name of country: #{addr.street.city.region.country.name}")
  </code></pre>
  
  <p>?</p>