多言語化の基盤作り (#55) (#421)

Reviewed-on: #421
Co-authored-by: miteruzo <miteruzo@naver.com>

backend/app/representations/deerjikist_repr.rb

@@ -6,11 +6,12 @@ module DeerjikistRepr
 
   module_function
 
-  def base deerjikist
-    deerjikist.as_json(BASE)
+  def base deerjikist, language_code: 'ja'
+    deerjikist.as_json(BASE).merge(
+        tag: deerjikist.tag && TagRepr.base(deerjikist.tag, language_code:))
   end
 
-  def many deerjikists
-    deerjikists.map { |d| base(d) }
+  def many deerjikists, language_code: 'ja'
+    deerjikists.map { |d| base(d, language_code:) }
   end
 end