make fetch_associated_object a public method on relationship class so it can be called from SerilizationCore class

lib/fast_jsonapi/relationship.rb

@@ -37,6 +37,11 @@ module FastJsonapi
       end
     end
 
+    def fetch_associated_object(record, params)
+      return object_block.call(record, params) unless object_block.nil?
+      record.send(object_method_name)
+    end
+
     private
 
     def include_relationship?(record, serialization_params)
@@ -80,11 +85,6 @@ module FastJsonapi
       end
     end
 
-    def fetch_associated_object(record, params)
-      return object_block.call(record, params) unless object_block.nil?
-      record.send(object_method_name)
-    end
-
     def fetch_id(record, params)
       unless object_block.nil?
         object = object_block.call(record, params)

lib/fast_jsonapi/serialization_core.rb

@@ -119,7 +119,7 @@ module FastJsonapi
             serializer = relationship_item.serializer.to_s.constantize
             relationship_type = relationship_item.relationship_type
 
-            included_objects = fetch_associated_object(record, relationship_item, params)
+            included_objects = relationship_item.fetch_associated_object(record, params)
             next if included_objects.blank?
             included_objects = [included_objects] unless relationship_type == :has_many
 
@@ -138,11 +138,6 @@ module FastJsonapi
           end
         end
       end
-
-      def fetch_associated_object(record, relationship, params)
-        return relationship.object_block.call(record, params) unless relationship.object_block.nil?
-        record.send(relationship.object_method_name)
-      end
     end
   end
 end