post_versions.tags_json への移行 (#354) (#415)

画面テストまだ．

Reviewed-on: #415
Co-authored-by: miteruzo <miteruzo@naver.com>

backend/app/controllers/application_controller.rb

@@ -85,4 +85,11 @@ class ApplicationController < ActionController::API
                    base_errors: },
            status:
   end
+
+  def normalise_json value
+    return nil if value.nil?
+    return JSON.parse(value) if value.is_a?(String)
+
+    value
+  end
 end