Provide dynamic fields mixin for serializers
Description / Overview
Dynamic fields, as in /submission/3/?fields=text will only return the text and nothing else.
Use cases
Provide a DRY way to enable the front-end to get only the data that is needed.
Links / references
https://github.com/dbrgn/drf-dynamic-fields http://www.django-rest-framework.org/api-guide/serializers/#dynamically-modifying-fields