title: Django REST framework serializer without a model
body: <p>I'm working on a couple endpoints which aggregate data. One of the endpoints will for example return an array of objects, each object corresponding with a day, and it'll have the number of comments, likes and photos that specific user posted. This object has a predefined/set schema, but we do not store it in the database, so it doesn't have a model.</p>
  
  <p>Is there a way I can still use Django serializers for these objects without having a model?</p>