미디어 업로드와 태그 표시 수정

db/migrations/055_add_post_tag_sort_order.sql

@@ -0,0 +1,21 @@
+ALTER TABLE post_tags
+  ADD COLUMN IF NOT EXISTS sort_order INTEGER NOT NULL DEFAULT 0;
+
+WITH ordered_post_tags AS (
+  SELECT
+    post_id,
+    tag_id,
+    (ROW_NUMBER() OVER (
+      PARTITION BY post_id
+      ORDER BY created_at ASC, tag_id ASC
+    ) - 1) * 10 AS next_sort_order
+  FROM post_tags
+)
+UPDATE post_tags
+SET sort_order = ordered_post_tags.next_sort_order
+FROM ordered_post_tags
+WHERE post_tags.post_id = ordered_post_tags.post_id
+  AND post_tags.tag_id = ordered_post_tags.tag_id;
+
+CREATE INDEX IF NOT EXISTS post_tags_post_id_sort_order_idx
+  ON post_tags (post_id, sort_order ASC, created_at ASC);