title: Laravel does not detect json with axios
body: <p>I'm sending an ajax request with <a href="https://github.com/mzabriskie/axios" rel="nofollow noreferrer">axios</a> with these headers:</p>
  
  <pre><code>window.axios.defaults.headers.common = {
      'X-CSRF-TOKEN': window.Laravel.csrfToken,
      'X-Requested-With': 'XMLHttpRequest',
      'Content-Type': 'application/json'
  };
  </code></pre>
  
  <p>But when I say this in a Laravel 5.4 controller:</p>
  
  <pre><code>if (request()-&gt;wantsJson()) {
      $forums = $this-&gt;forumInfo-&gt;index(Auth::user());
      return response()-&gt;json(compact('forums'), 200);
  }
  
  return view('home');
  </code></pre>
  
  <p>The json request is not detected. Also when I look into my headers in chrome dev I can see:</p>
  
  <pre><code>Content-Type:text/html; charset=UTF-8
  </code></pre>
  
  <p>Why does the header not change approximately to a json content type?</p>