feat: performance improvement replace slug index with covering index

db/migrations/20250318072657_replace_slug_index_with_covering_index.sql

@@ -0,0 +1,10 @@
+-- +micrate Up
+-- SQL in section 'Up' is executed when this migration is applied
+DROP INDEX IF EXISTS index_links_slug;
+-- Create the new covering index that includes id and url
+CREATE INDEX IF NOT EXISTS idx_links_slug ON links (id, slug, url);
+
+-- +micrate Down
+-- SQL in section 'Down' is executed when this migration is rolled back
+DROP INDEX IF EXISTS idx_links_slug;
+CREATE INDEX IF NOT EXISTS index_links_slug ON links (slug);