Add admin capcodes

Sometimes, it is necessary for an admin or other moderator to reveal
themselves. Capcodes allow them to do so by appending a special colored
portion at the end of their name on a post.

This adds object-level permissions, so if you have a moderator who
shouldn't be able to use the "admin" capcode, you can give them
permission only to the "moderator" capcode.

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

board/forms.py

@@ -1,3 +1,4 @@
+from django.core.exceptions import ValidationError
 from django.conf import settings
 from django.db import transaction
 from django.db.models import Q
@@ -39,12 +40,21 @@ class ReplyForm(PostForm):
 
     class Meta:
         model = Post
-        fields = ["name", "text", "bump", "image"]
+        fields = ["name", "text", "bump", "capcode", "image"]
 
-    def __init__(self, *args, op, reply, **kwargs):
+    def __init__(self, *args, user, op, **kwargs):
         super(ReplyForm, self).__init__(*args, **kwargs)
         self.instance.op = op
-        self.instance.reply = reply
+        self.user = user
+
+    def clean(self):
+        super().clean()
+        # TODO
+        # Check if the user has the right permissions to use the selected capcode
+        capcode = self.cleaned_data["capcode"]
+        if capcode:
+            if not self.user or not self.user.has_perm("board.use_capcode", capcode):
+                raise ValidationError("Could not create post")
 
 
 class ReportForm(ModelForm):