This is the same as:
public function run()
{
$posts = array(
array( 'title' => 'My first post', 'body' => 'My post' ),
array( 'title' => 'My second post', 'body' => 'My post' )
);
DB::table('posts')->insert($posts);
}
It is the newer (>= PHP 5.4) short way of defining an array.