Does Laravel Schema manages polymorphic associations out of the box?

Question

I'd like to create some commentable models for a project, but I cannot find any references to create the comments migration script, I've only found this video on vimeo: Laravel 4 - Eloquent Collections & Polymorphic Relations.

Am I supposed to add the polymorphic columns explicitly?

Schema::create('comments',function($table){
    $table->increments('id');
    $table->text('body');
    $table->string('commentable_type');
    $table->integer('commentable_id');
    $table->timestamps();
});

Question comes as the builder do expects the programmer when a key is a foreign key as in $table->foreign('user_id')->references('id')->on('users');

Answer 1

Laravel ~4.1 has a method to accomplish this:

$table->morphs('itemable');

Creates:

itemable_id
itemable_type
table_name_itemable_id_itemable_type_index

Second optional parameter is a replacement index name if the index is too long. The signature is:

public function morphs($name, $indexName = null);