-- Add password change tracking to users table
-- NULL means password has never been changed (first login)
-- Timestamp indicates when password was last changed

ALTER TABLE users
ADD COLUMN password_changed_at TIMESTAMP NULL DEFAULT NULL
AFTER password;

-- Set password_changed_at to NULL for all existing users (they need to change password on next login)
-- This ensures existing users are not forced to change password immediately
-- New users will have NULL by default and will be forced to change on first login

