backend/app/models/tag.rb

@@ -67,6 +67,14 @@ class Tag < ApplicationRecord
     @bot ||= find_or_create_by_tag_name!('bot操作', category: :meta)
   end
 
+  def self.video
+    @video ||= find_or_create_by_tag_name!('動画', category: :meta)
+  end
+
+  def self.niconico
+    @niconico ||= find_or_create_by_tag_name!('ニコニコ', category: :meta)
+  end
+
   def self.normalise_tags tag_names, with_tagme: true, deny_nico: true
     if deny_nico && tag_names.any? { |n| n.start_with?('nico:') }
       raise NicoTagNormalisationError

backend/lib/tasks/sync_nico.rake

@@ -91,7 +91,7 @@ namespace :nico do
         end
         post.save!
         post.resized_thumbnail!
-        sync_post_tags!(post, [Tag.tagme.id])
+        sync_post_tags!(post, [Tag.tagme.id, Tag.bot.id, Tag.niconico.id, Tag.video.id])
       end
 
       kept_ids = PostTag.kept.where(post_id: post.id).pluck(:tag_id).to_set