Added drf-haystack to third party resources

docs/topics/third-party-resources.md

@@ -246,6 +246,7 @@ To submit new content, [open an issue][drf-create-issue] or [create a pull reque
 * [django-versatileimagefield][django-versatileimagefield] - Provides a drop-in replacement for Django's stock `ImageField` that makes it easy to serve images in multiple sizes/renditions from a single field. For DRF-specific implementation docs, [click here][django-versatileimagefield-drf-docs].
 * [drf-tracking][drf-tracking] - Utilities to track requests to DRF API views.
 * [django-rest-framework-braces][django-rest-framework-braces] - Collection of utilities for working with Django Rest Framework. The most notable ones are [FormSerializer](https://django-rest-framework-braces.readthedocs.org/en/latest/overview.html#formserializer) and [SerializerForm](https://django-rest-framework-braces.readthedocs.org/en/latest/overview.html#serializerform), which are adapters between DRF serializers and Django forms.
+* [drf-haystack][drf-haystack] - Haystack search for Django Rest Framework
 
 ## Other Resources
 
@@ -345,3 +346,4 @@ To submit new content, [open an issue][drf-create-issue] or [create a pull reque
 [django-rest-framework-braces]: https://github.com/dealertrack/django-rest-framework-braces
 [dry-rest-permissions]: https://github.com/Helioscene/dry-rest-permissions
 [django-url-filter]: https://github.com/miki725/django-url-filter
+[drf-haystack]: http://drf-haystack.readthedocs.org/en/latest/