Email Cron Scheduler

// Scheduled Action Hook
function gmg_forms_emails_updater( ) {
}
add_action( 'gmg_forms_emails_updater', 'gmg_forms_emails_updater' );

// Custom Cron Recurrences
function gmg_update_emails_cron_activation_recurrence( $schedules ) {
	$schedules['fifteenMinutes'] = array(
		'display' => __( 'Fifteen Minutes', 'textdomain' ),
		'interval' => 900,
	);
	return $schedules;
}
add_filter( 'cron_schedules', 'gmg_update_emails_cron_activation_recurrence' );

// Schedule Cron Job Event
function gmg_update_emails_cron_activation() {
	if ( ! wp_next_scheduled( 'gmg_forms_emails_updater' ) ) {
		wp_schedule_event( current_time( 'timestamp' ), 'fifteenMinutes', 'gmg_forms_emails_updater' );
	}
}
add_action( 'wp', 'gmg_update_emails_cron_activation' );