관리자와 회원 설정 계정 작업 정리

db/migrations/021_add_member_previous_login.sql

@@ -0,0 +1,12 @@
+ALTER TABLE users
+  ADD COLUMN IF NOT EXISTS previous_last_seen_at TIMESTAMPTZ;
+
+ALTER TABLE users
+  ADD COLUMN IF NOT EXISTS previous_last_seen_ip TEXT NOT NULL DEFAULT '';
+
+UPDATE users
+SET
+  previous_last_seen_at = last_seen_at,
+  previous_last_seen_ip = last_seen_ip
+WHERE previous_last_seen_at IS NULL
+  AND last_seen_at IS NOT NULL;