Convert includes from camel to snake case (#257)

Author: birkholz

Diff for: rest_framework_json_api/renderers.py

@@ -4,6 +4,7 @@
 import copy
 from collections import OrderedDict
 
+import inflection
 from django.utils import six, encoding
 from rest_framework import relations
 from rest_framework import renderers
@@ -237,6 +238,7 @@ def extract_included(fields, resource, resource_instance, included_resources):
         context = current_serializer.context
         included_serializers = utils.get_included_serializers(current_serializer)
         included_resources = copy.copy(included_resources)
+        included_resources = [inflection.underscore(value) for value in included_resources]
 
         for field_name, field in six.iteritems(fields):
             # Skip URL field

Diff for: rest_framework_json_api/serializers.py

@@ -1,3 +1,4 @@
+import inflection
 from django.utils.translation import ugettext_lazy as _
 from rest_framework.exceptions import ParseError
 from rest_framework.serializers import *
@@ -75,7 +76,7 @@ def validate_path(serializer_class, field_path, path):
             serializers = get_included_serializers(serializer_class)
             if serializers is None:
                 raise ParseError('This endpoint does not support the include parameter')
-            this_field_name = field_path[0]
+            this_field_name = inflection.underscore(field_path[0])
             this_included_serializer = serializers.get(this_field_name)
             if this_included_serializer is None:
                 raise ParseError(