title: Django inlineformset_factory and ManyToMany fields
body: <p>I'm attempting to create a formset for the following models:</p>
  
  <pre><code>class Category(models.Model):
  
      name = models.CharField(max_length=100, unique=True)
      description = models.TextField(null = True, blank=True)
  
  class Recipe(models.Model):
      title = models.CharField(max_length=100)
      body = models.TextField()
      user = models.ForeignKey(User)
      categories = models.ManyToManyField(Category, null = True, blank = True)
  </code></pre>
  
  <p>But any time I try to implement a formset, like so:</p>
  
  <pre><code>FormSet = inlineformset_factory(Category, Recipe, extra=3)
          formset = FormSet()
  </code></pre>
  
  <p>I get an error stating that no ForeignKey is present in the Category model. Is it possible to build a formset using a ManyToManyField, or to replicate this functionality in some way? </p>
  
  <p>Thanks!</p>