title: How do you make a Django app pluggable?
body: <p>Say for example I have a Blog app that I want to be able to drop into different projects, but I always want the Blog to be associated with some other model. For example, in one case I may want it to be associated with a user:</p>
  
  <p>site.com/someuser/blog</p>
  
  <p>But on another site I want it to be associated with, say, a school:</p>
  
  <p>site.com/someschool/blog</p>
  
  <p>Is there a way to make the Blog app pluggable so that it's not necessary to redefine the model (adding a foreign key field) whenever I drop it into a project?</p>