diff --git a/gem/lib/servus.rb b/gem/lib/servus.rb
index 826299c..90a40a2 100644
--- a/gem/lib/servus.rb
+++ b/gem/lib/servus.rb
@@ -4,6 +4,7 @@
 require 'json-schema'
 require 'active_support'
 require 'active_support/core_ext/class/attribute'
+require 'active_support/core_ext/hash/indifferent_access'
 require 'active_model_serializers'
 
 # Servus namespace