added uuid query scope

README.md

@@ -102,6 +102,20 @@ And to retrieve meta information, use the 'read' method.
 $post->read('author'); //returns 'Bob Saget'
 ```
 
+### Query Builder
+
+Let's say you need to retrieve the post that has a certain UUID (maybe you gave it out in a url or something)
+
+It's super easy to search for it:
+``` php
+Post::withUuid($uuid)->first();
+```
+
+It is completely integrated into the query builder, so you can still do stuff like:
+``` php
+Post::withUuid($uuid)->pluck('username');
+Post::withUuid($uuid)->firstOrFail();
+```
 
 ## Credits