Swap out KeyTransform for CaseTransform (rails-api#1993)

* delete KeyTransform, use CaseTransform

* added changelog

CHANGELOG.md

@@ -15,6 +15,7 @@ Fixes:
 Misc:
 
 - [#1984](https://github.com/rails-api/active_model_serializers/pull/1984) Make test attributes explicit. Test models have 'associations' support. (@bf4)
+- [#1993](https://github.com/rails-api/active_model_serializers/pull/1993) Swap out KeyTransform for CaseTransform gem for the possibility of native extension use (@NullVoxPopuli)
 
 ### [v0.10.3 (2016-11-21)](https://github.com/rails-api/active_model_serializers/compare/v0.10.2...v0.10.3)
 

active_model_serializers.gemspec

@@ -43,6 +43,7 @@ Gem::Specification.new do |spec|
   # 'thread_safe'
 
   spec.add_runtime_dependency 'jsonapi', '0.1.1.beta2'
+  spec.add_runtime_dependency 'case_transform', '>= 0.2'
 
   spec.add_development_dependency 'activerecord', rails_versions
   # arel

lib/active_model_serializers/adapter/base.rb

@@ -1,4 +1,4 @@
-require 'active_model_serializers/key_transform'
+require 'case_transform'
 
 module ActiveModelSerializers
   module Adapter
@@ -31,7 +31,7 @@ def self.transform(options)
       # @param options [Object] serializable resource options
       # @return [Symbol] the default transform for the adapter
       def self.transform_key_casing!(value, options)
-        KeyTransform.send(transform(options), value)
+        CaseTransform.send(transform(options), value)
       end
 
       def self.cache_key

lib/active_model_serializers/adapter/json_api/deserialization.rb

@@ -205,7 +205,7 @@ def parse_relationships(relationships, options)
         # @api private
         def transform_keys(hash, options)
           transform = options[:key_transform] || :underscore
-          KeyTransform.send(transform, hash)
+          CaseTransform.send(transform, hash)
         end
       end
     end