title: Laravel command - Only optional argument
body: <p>I have a command with this signature</p>
  
  <pre><code>order:check {--order}
  </code></pre>
  
  <p>And execute this:</p>
  
  <pre><code>php artisan order:check --order 7
  </code></pre>
  
  <p>For some reason that results in this exception</p>
  
  <pre><code>  [RuntimeException]                                 
    Too many arguments, expected arguments "command".  
  </code></pre>
  
  <p>Why? I want that this command can either be executed as <code>php artisan order:check</code> or with an optional order id <code>php artisan order:check --order X</code></p>