laravel/framework — pull request #5346 by JosephSilber (2014-08-05 22:40:19+00:00)
Title: Reduce with no callback should reduce the array

If no callback is passed to `reduce`, it will now collapse a multi-dimensional array into a single array.

---

Sample usage:

```php
// Get all tags for the latest blog posts
$tags = Post::with('tags')->latest()->take(30)->get()->fetch('tags')->reduce()->unique();
```