title: How to count and display objects in relation ManyToMany in Django
body: <p>I have a simple model with news and categories:</p>
  
  <pre><code>class Category(models.Model):
      name = models.CharField()
      slug = models.SlugField()
  
  class News(models.Model):
      category = models.ManyToManyField(Category)
      title = models.CharField()
      slug = models.SlugField()
      text = models.TextField()
      date = models.DateTimeField()
  </code></pre>
  
  <p>I want to count news for each category and display it on the website, like this:</p>
  
  <pre><code>Sport (5)
  School (4)
  Films (6)
  Computer (2)
  etc...
  </code></pre>
  
  <p>How can I do this??</p>
  
  <p>Thanks!</p>