title: Foreign key data in admin
body: <p>Is there any way I can display the total number attending a course in the <code>list_display</code> of CourseAdmin?</p>
  
  <p><em>admin.py</em></p>
  
  <pre><code>class Attendee_Inline(admin.TabularInline):
      model = Attendee
      extra = 5
  
  class CourseAdmin(admin.ModelAdmin):
      inlines = [Attendee_Inline]
      list_display = ('date','course_name','course','venue','maximum_attendees','get_count')
  </code></pre>
  
  <p>I tried the following:</p>
  
  <pre><code>def get_count(self,request):
      this = self.id
      q = Attendee.objects.get(pk=this).count()
      return q
  </code></pre>