title: Laravel $request->input('var') returns null in Controller
body: <p>//routes</p>
  
  <pre><code>Route::get('/section/{id}', 'Controller@section');
  </code></pre>
  
  <p>//controller</p>
  
  <pre><code>public function section(Request $request) {
    $id = $request-&gt;input('id');
    dd($id);
  }
  </code></pre>
  
  <p>//output</p>
  
  <pre><code>null
  </code></pre>
  
  <ol>
  <li>there is no problem to retrieve $id, if I try to retrieve inside Route through function($id){}.</li>
  <li>no other kind of errors shown.</li>
  </ol>
  
  <p>Thank you.</p>