Why is there no very famous open source CMS or e-commerce application written in Ruby?
The very famous open source CMS and e-commerce applications, i.e. Wordpress, Joomla, Drupal, Prestashop, are all written in PHP.  
But Ruby is awesome.  
Why is there no such project written in Ruby?  
Or would there be one I do not know?
Why is there no very famous open source CMS or e-commerce application written in Ruby?
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The very famous open source CMS and e-commerce applications, i.e. Wordpress, Joomla, Drupal, Prestashop, are all written in PHP.  
But Ruby is awesome.  
Why is there no such project written in Ruby?  
Or would there be one I do not know?