title: Undefined offset: 1 error for laravel validation
body: <p>I have some validation on my form in laravel to ensure the gift the user is claiming is one assigned to their campaign with the below code</p>
  
  <pre><code>'gift_id' =&gt; 'required|int|exists:gifts,campaign_id,' . \Auth::user()-&gt;campaign-&gt;id,
  </code></pre>
  
  <p>But on form submission I am getting the following error </p>
  
  <blockquote>
    <p>ErrorException in ValidatesAttributes.php line 721:
        Undefined offset: 1</p>
  </blockquote>
  
  <p>Could someone please help me out?</p>
  
  <p>Thanks</p>