title: ManyToManyField causing Django Model Save Problems
body: <p>I want to save a Django model instance with a ManyToManyField.  When I try to do so with the create() manager, it produces the following error:</p>
  
  <pre><code> Exception Value:'post' is an invalid keyword argument for this function
  </code></pre>
  
  <p>Here is my model:</p>
  
  <pre><code>    class Amenity(models.Model):
         post=models.ManyToManyField(Post,blank=True,null=True)
         name=models.CharField(max_length=50, choices=AMENITIES)
  
          def __unicode__(self):
              return str(self.name)
  </code></pre>
  
  <p>Here is the relevant part of the view:</p>
  
  <pre><code>  if request.POST.get('amenities'):
              amens=request.POST['amenities'].split(',')
              p=int(post.id)      
              for a in amens:
                  Amenity.objects.create(post=p,name=a)
              return HttpResponse('success')
  </code></pre>
  
  <p>I'm trying to save multiple amenities at one time and I'd doing so outside of a modelform because I have design in mind and I didn't want to have to create a custom field in this case. </p>
  
  <p>post.id is returning the correct value here, so that doesn't seem to be the issue. </p>
  
  <p>Thanks!</p>