title: Django Selectmultiple
body: <p>First of all, excuse for my english ^^</p>
  
  <p>I don't understand how i can use the select multiple widget in django.
  I mean, i don't understang which files and functions are necessary.</p>
  
  <p>Example, I have two classes :</p>
  
  <pre><code>class Student(models.Model):
      name=models.CharField(max_length=100)
      subject=models.ManyToManyField(Subjects)
  class Subjects(models.Model):
      sub_name=models.CharField(max_length=100)
      desc=models.CharField(max_length=100)
  </code></pre>
  
  <p>And now, i want to use the select multiple widget, so which files and functions are necessary ?</p>
  
  <p>I hope you understand what I'm asking ^^</p>
  
  <p>Tks :)</p>