広場投稿追加画面の刷新 (#399) (#413)

Reviewed-on: #413
Co-authored-by: miteruzo <miteruzo@naver.com>
Co-committed-by: miteruzo <miteruzo@naver.com>

backend/app/services/post_thumbnail_attachment_builder.rb

@@ -0,0 +1,11 @@
+class PostThumbnailAttachmentBuilder
+  def self.build thumbnail:, thumbnail_base:
+    if thumbnail_base.present?
+      return Post.remote_thumbnail_attachment(thumbnail_base)
+    end
+
+    return nil if thumbnail.blank?
+
+    Post.resized_thumbnail_attachment(thumbnail)
+  end
+end