Custom Post Type as Plugin

my-cpt.php

<?php
/*
Plugin Name: A Custom Post Type
Plugin URI: http://kaska.jp/
Description: A simple barebones custom post type.
Version: 1.0
Author: Jonas Raneryd
Author URI: http://kaska.jp/
License: MIT
*/

add_action( 'init', 'register_cpt_acpt' );

function register_cpt_acpt() {
	$labels = array( 
		'name' => _x( 'Something', 'acpt' ),
		'singular_name' => _x( 'Something', 'acpt' ),
		'add_new' => _x( 'Add new', 'acpt' ),
		'add_new_item' => _x( 'Add new something', 'acpt' ),
		'edit_item' => _x( 'Edit something', 'acpt' ),
		'new_item' => _x( 'New something', 'acpt' ),
		'view_item' => _x( 'View something', 'acpt' ),
		'search_items' => _x( 'Search something', 'acpt' ),
		'not_found' => _x( 'No somethings found', 'acpt' ),
		'not_found_in_trash' => _x( 'No somethings found in the trash', 'acpt' ),
		'parent_item_colon' => _x( 'Parent Something:', 'acpt' ),
		'menu_name' => _x( 'Somethings', 'acpt' ),
	);

	$args = array( 
		'labels' => $labels,
		'hierarchical' => false,
		'supports' => array( 'title' ),
		'public' => true,
		'show_ui' => true,
		'show_in_menu' => true,
		'menu_position' => 5,
		'show_in_nav_menus' => true,
		'publicly_queryable' => true,
		'exclude_from_search' => true,
		'has_archive' => true,
		'query_var' => true,
		'can_export' => true,
		'rewrite' => true,
		'capability_type' => 'post'
	);

	register_post_type( 'acpt', $args );
}
?>