Flush WordPress Rewrite Rule if you have changes on a document

wp-flush-rules.php

<?php
	/**
	 * validate the last modification of this file
	 * on modification flush rewrite rules
	 *
	 * @return void
	 */
	function _flush_rules() {

		$o = __CLASS__;
		$v = filemtime( __FILE__ );
		$d = array( 'version' => 0, 'time' => time() );
		$r = wp_parse_args( get_option( $o, array() ), $d );

		if ( $r[ 'version' ] != $v ) {

			flush_rewrite_rules();

			$a = array( 'version' => $v, 'time' => time() );

			if ( ! update_option( $o, $a ) ) {
				add_option( $o, $a );
			}
		}
	}