title: There are no commands defined in the "setup" namespace : Magento 2
body: <p>I have installed <code>latest version of Megento 2</code>, everything is working fine frontend, backend and functionality. </p>
  
  <p>I have one issue with  <code>bin/magento setup:upgrade</code> command, when I run this command in terminal I get below exception .</p>
  
  <blockquote>
    <p>[InvalidArgumentException]<br>
    There are no commands defined in the "setup" namespace.</p>
  </blockquote>
  
  <p><strong>Screenshot :</strong></p>
  
  <p><a href="https://i.stack.imgur.com/l72FB.png" rel="noreferrer"><img src="https://i.stack.imgur.com/l72FB.png" alt="enter image description here"></a></p>
  
  <p>Is there any thing I missed during installation or I need to install some package to let it working?</p>