#419

backend/app/controllers/tags_controller.rb

@@ -265,14 +265,17 @@ class TagsController < ApplicationController
   end
 
   def show
-    tag = Tag.joins(:tag_name)
-             .includes(:tag_name, :materials, tag_name: :wiki_page)
-             .find_by(id: params[:id])
-    if tag
-      render json: TagRepr.base(tag)
-    else
-      head :not_found
-    end
+    tag =
+        Tag
+        .joins(:tag_name)
+        .includes(:tag_name, :materials, tag_name: :wiki_page)
+        .find_by(id: params[:id])
+    return render json: TagRepr.base(tag) if tag
+
+    external_tag = ExternalTag.find_by(id: params[:id])
+    return render json: ExternalTagRepr.base(external_tag) if external_tag
+
+    head :not_found
   end
 
   def show_by_name