title: Django ORM. Retrieve 10 items for each category
body: <p>I have 2 models in My Django REST.</p>
  
  <pre><code>class Category(models.Model):
      name = models.CharField()
  
  class Item(models.Model):
      name = models.CharField()
      category = models.ForeignKey(Category)
  </code></pre>
  
  <p>I need build queryset where i get 10 items for each category.
  I dont know i need Filter Category or Item, but maybe somebody can help me.</p>
  
  <p>I think i need something like this:
      Item.objects.filter.. if item with same category not > 10.</p>
  
  <p>I will be pleasure if somebody show me some way or decision.</p>