ALTER TABLE users ADD COLUMN confirmed_at VARCHAR(64) NULL;
UPDATE users SET confirmed_at = CURRENT_TIMESTAMP WHERE confirmed_at IS NULL;
CREATE TABLE account_confirmation_tokens (
 token VARCHAR(128) PRIMARY KEY,
 user_id BIGINT NOT NULL,
 expires_at VARCHAR(64) NOT NULL,
 used_at VARCHAR(64),
 created_at VARCHAR(64) NOT NULL DEFAULT (CURRENT_TIMESTAMP),
 CONSTRAINT fk_account_confirmation_user FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
 INDEX idx_account_confirmation_user (user_id)
) ENGINE=InnoDB;