add migration system

backend/internal/db/health.sql.go

@@ -0,0 +1,21 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.31.1
+// source: health.sql
+
+package db
+
+import (
+	"context"
+)
+
+const getHealth = `-- name: GetHealth :one
+SELECT 1 AS ok
+`
+
+func (q *Queries) GetHealth(ctx context.Context) (int64, error) {
+	row := q.db.QueryRowContext(ctx, getHealth)
+	var ok int64
+	err := row.Scan(&ok)
+	return ok, err
+}