Add link to serpy serialization, fixes #3391

docs/api-guide/serializers.md

@@ -1032,6 +1032,9 @@ The following third party packages are also available.
 
 The [django-rest-marshmallow][django-rest-marshmallow] package provides an alternative implementation for serializers, using the python [marshmallow][marshmallow] library. It exposes the same API as the REST framework serializers, and can be used as a drop-in replacement in some use-cases.
 
+## Serpy
+The [serpy][serpy] package is an alternative implementation for serializers that is built for speed. [Serpy][serpy] serializes complex datatypes to simple native types. The native types can be easily converted to JSON or any other format needed.
+
 ## MongoengineModelSerializer
 
 The [django-rest-framework-mongoengine][mongoengine] package provides a `MongoEngineModelSerializer` serializer class that supports using MongoDB as the storage layer for Django REST framework.
@@ -1050,6 +1053,7 @@ The [django-rest-framework-hstore][django-rest-framework-hstore] package provide
 [encapsulation-blogpost]: http://www.dabapps.com/blog/django-models-and-encapsulation/
 [django-rest-marshmallow]: http://tomchristie.github.io/django-rest-marshmallow/
 [marshmallow]: https://marshmallow.readthedocs.org/en/latest/
+[serpy]: https://github.com/clarkduvall/serpy
 [mongoengine]: https://github.com/umutbozkurt/django-rest-framework-mongoengine
 [django-rest-framework-gis]: https://github.com/djangonauts/django-rest-framework-gis
 [django-rest-framework-hstore]: https://github.com/djangonauts/django-rest-framework-hstore