Add user post deletion

Users can delete their posts as long as they don't clear their cookies,
and as long as server-side user sessions are persistent.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

board/forms.py

@@ -25,11 +25,12 @@ class PostForm(ModelForm):
         model = Post
         fields = ["subject", "name", "text", "capcode", "image"]
 
-    def __init__(self, *args, user, board, ip, **kwargs):
+    def __init__(self, *args, user, board, ip, user_token, **kwargs):
         super(PostForm, self).__init__(*args, **kwargs)
         self.user = user
         self.instance.board = board
         self.instance.ip = ip
+        self.instance.user_token = user_token
         self.fields["capcode"].queryset = get_objects_for_user(
             self.user, "board.use_capcode"
         )