Remove the slug from published cpt post permalinks.

remove_cpt_prefix.php

<?php

	/**
	 * Remove the slug from published post permalinks.
	 * Only affect to our custom post type, though.
	 */
	add_filter("post_type_link", "wphdlr_remove_post_type_slug", 10, 3);
	function wphdlr_remove_post_type_slug($post_link, $post, $leavename)
		{
			if (!in_array("users", $post->post_type))
				{
					return $post_link;
				}

			$post_link	= str_replace("/" . $post->post_type . "/", "/", $post_link);

			return $post_link;
		}

	/**
	 * Have WordPress match postname to any of our public post types (post, page, race)
	 * All of our public post types can have /post-name/ as the slug, so they better be unique across all posts
	 * By default, core only accounts for posts and pages where the slug is /post-name/
	 *
	 * This function remove Custom Post Type base : http://localhost/user/wprelic to http://localhost/wprelic
	 */
	add_action("pre_get_posts", "wphdlr_cpt_parse_request");
	function wphdlr_cpt_parse_request($query)
		{
			/**
			 * Only main query.
			 */
			if (!$query->is_main_query())
				return;

			/**
			 * Only for our very specific rewrite rule match.
			 */
			if (2 != count($query->query) || !isset($query->query['page']))
				return;

			/**
			 * 'name' will be set if post permalinks are just post_name, otherwise the page rule will match.
			 */
			if (!empty($query->query["name"]))
				{
					$query->set("post_type", array("page"));
				}
		}