title: Django: How to integrate an app inside another app
body: <p>i would like to know how can we "call" an application from inside a different application.
  Basically, i have, for example :</p>
  
  <ul>
  <li>a Calendar app that does a certain process to render a calendar in html</li>
  <li>a "Main" app that shows the index.html of a website</li>
  </ul>
  
  <p>I would like the Main app to invoke the Calendar app and insert what it renders in the sidebar.</p>
  
  <p>The CodeIgniter framework for example, can handle that. A controller can invoke another controller, saves what it returns (the html output) in a variable, and finally includes this variable in the context that will be used to render the final html file.</p>
  
  <p>Is that possible with Django ?
  Thanks</p>