title: How to automatically keep Satis up to date with the latest dependencies from all my projects?
body: <p><a href="https://github.com/composer/satis" rel="nofollow">Satis</a> essentially creates a local mirror of packagist and it can download copies of all the packages you need to keep them cached.</p>
  
  <p>The problem is that you have to specify all your dependencies up front. With several projects with ever-changing dependencies, keeping Satis up to date is a nightmare.</p>
  
  <p>How I envisioned Satis working is that when I run <code>composer install</code> on my project it would ask Satis for a copy of each of my dependencies. If Satis didn't already have it cached, it would query Packagist, download a copy, and then serve it to me. The next time I install it would be cached. If Pacakgist then goes down, or the project maintainer deletes his repo off Github, it won't matter because Satis has kept a copy.</p>
  
  <p>Is there a way to make Satis behave this way? Or is there an alternative Packagist mirror that does this?</p>