title: Laravel Order By Specific String
body: <p>I have data on my <strong>PostgreSQL</strong> like this :</p>
  
  <p><strong>background</strong></p>
  
  <pre><code>id | Size
  1  | small
  2  | medium
  3  | large
  </code></pre>
  
  <p><strong>art</strong></p>
  
  <pre><code>id | name       | background_id
  1  | Shine      | 1
  2  | Sun        | 3
  3  | Mountain   | 3
  </code></pre>
  
  <p>I want to get art data orderBy background by it's value from small (small, medium, large) with laravel eloquent</p>
  
  <pre><code>Art::with( [ 'background' =&gt; function( $background ) {
      $background-&gt;oderBy( DB::raw( "what is this?" ) );
  } ] )-&gt;get();
  </code></pre>
  
  <p>How to fix it?</p>
  
  <pre><code>FIELD(type, 'S', 'M', 'L', 'XL')
  </code></pre>
  
  <p>is not working</p>