Create post factory with relationships fields

Laravel_Factory_Relationships.php

//create 15 posts with 3 comments and 3 tags each
$posts = factory('App\Post', 15)
    ->create()
    ->each(function($post) {
    foreach(range(1,3) as $v){
           $post->comments()->save(factory('App\Comment')->make());
       $post->tags()->save(factory('App\Tag')->make());
        }
    });