タグ “廃止” 追加 (#378) (#379)

Reviewed-on: http://git.miteruzo.com/miteruzo/btrc-hub/pulls/379
Co-authored-by: miteruzo <miteruzo@naver.com>
Co-committed-by: miteruzo <miteruzo@naver.com>

backend/app/representations/wiki_page_repr.rb

@@ -2,7 +2,7 @@
 
 
 module WikiPageRepr
-  BASE = { methods: [:title] }.freeze
+  BASE = { methods: [:title, :deprecated_at] }.freeze
 
   module_function