add preview_image field to post model

blog_ext/models.py

@@ -34,6 +34,13 @@ Section._meta.get_field('enabled').verbose_name = _('Включенно')
 
 
 class Post(BasePost, AbstractStatusModel):
+    def upload_file_to(self, filename):
+        return "blog_ext/{post}/{filename}".format(**{
+            'post': self.post.slug,
+            'filename': filename
+        })
+
+    preview_image = models.FileField(_('Превью изображение'), upload_to=upload_file_to, null=True, blank=True)
 
     @property
     def sharable_url(self):