WordPress: Add Post ID to Admin Posts/Pages

functions.php

add_filter('manage_posts_columns', 'we_posts_columns_id', 5);
add_action('manage_posts_custom_column', 'we_posts_custom_id_columns', 5, 2);
add_filter('manage_pages_columns', 'we_posts_columns_id', 5);
add_action('manage_pages_custom_column', 'we_posts_custom_id_columns', 5, 2);
/**
* Add Post ID to posts, pages admin columns
*
*/
function we_posts_columns_id($defaults){
	$defaults['we_post_id'] = __('ID');
	return $defaults;
}
function we_posts_custom_id_columns($column_name, $id){
	if($column_name === 'we_post_id'){
		echo $id;
    }
}