title: best practice how to schedule symfony2 action
body: <p>My application based on symfony2 has to do some standalone jobs at differents moments and differents frequencies. For exemple, sending newsletter, editing report ...</p>
  
  <p>I want to be able to add/edit each task from the application
  My task would be very close to cron jobs and will consist to call a specific url.</p>
  
  <h2>From my point of view :</h2>
  
  <p>I think about creating a cron job that launch a script every half hour, or ten minutes. this script only do a curl command witch get a docronjob action. This docronjobaction is inside symfony and is responsible to get all the task and launch the one it has to.</p>
  
  <h2>My questions are :</h2>
  
  <ul>
  <li>Is there a cleaner way to achive that ?</li>
  <li>Inside the docronaction how do I launch others action ?</li>
  <li>How do I manage to set the time limit to 0 for an entire controller ?</li>
  <li>Does a bundle doing this allready exist ?</li>
  </ul>