Resource documentation.

        .. versionadded:: 0.7.2
            Content-Type check

        :return django.http.HttpResponse

def documentation(self, request):
        """ Resource documentation.

        .. versionadded:: 0.7.2
            Content-Type check

        :return django.http.HttpResponse

        """
        self.update_urls(request)
        context = {
            "resources": sorted(self.resource_map.items())
        }
        return render(request, "jsonapi/index.html", context)