title: Laravel - push array to collection
body: <p>I have this code where I try to grab all auth user categories:</p>
  
  <pre><code>$cats = Auth::user()-&gt;cats()-&gt;lists('title','id');
  </code></pre>
  
  <p>and I want to add new data to $cats so I write:</p>
  
  <pre><code> $cats-&gt;push(['5','BMW']);
  </code></pre>
  
  <p>but I got:</p>
  
  <pre><code>    Collection {#459 ▼
    #items: array:2 [▼
      9 =&gt; "asd"
      10 =&gt; array:2 [▼
        0 =&gt; "5"
        1 =&gt; "BMW"
      ]
    ]
  }
  </code></pre>
  
  <p>How I to change my code to get this result:</p>
  
  <pre><code>Collection {#459 ▼
    #items: array:2 [▼
      9 =&gt; "asd"
      5 =&gt; "BMW"
    ]
  }
  </code></pre>
  
  <p>So how I can add the array to this collection? 
  p.s. I need this format because I use select2 jquery plugin</p>