[Wordpress] Insert custom menu items via hard coding

wp-navmenu-insert-item.php

<?php
// Sample: Add HOME link to Nav Menu
function new_nav_menu_items($items, $args) {
    if( $args->theme_location == 'primary' ){
        $homelink = '<li class="home"><a href="' . home_url( '/' ) . '">' . __('Home') . '</a></li>';
        $items = $homelink . $items;
    }
    return $items;
}
add_filter( 'wp_nav_menu_items', 'new_nav_menu_items', 10, 2 );

/*
Source:
http://wordpress.stackexchange.com/a/60442/1044
*/