Merge pull request #185 from MarkusQ/fix-for-lighthouse-1475

This fixes lighthouse#1475, results incorrectly marked as immutable

Author: tpitale

lib/dm-core/model.rb

@@ -593,7 +593,8 @@ def load(records, query)
             model     = discriminator && discriminator.load(record[discriminator]) || self
             model_key = model.key(repository_name)
 
-            resource = if model_key.valid?(key_values = record.values_at(*model_key))
+            key_values = model_key.zip(record.values_at(*model_key)).map { |k,v| k.load(v) }
+            resource = if model_key.valid?(key_values)
               identity_map = repository.identity_map(model)
               identity_map[key_values]
             end