title: laravel 5.6 keep array custom key in resource response
body: <p>from laravel documentation:
  The withoutWrapping method only affects the outer-most response and will not remove data keys that you manually add to your own resource collections.</p>
  
  <p>i use Resource::withoutWrapping();</p>
  
  <pre><code>`"status": "success"
      "entry": {
          "access_control": [
              1 =&gt; {
                  "allowed": [
                      0 =&gt; "015"
                      1 =&gt; "002"
                      2 =&gt; "011"
                   ]
  }`
  </code></pre>
  
  <p>in laravel 5.6 i can't define custom array key, key under <code>access_control</code> key become 0.'</p>
  
  <p>How to make api resource support custom key?</p>