diff --git a/lib/bitmask_attributes.rb b/lib/bitmask_attributes.rb
index a8d00bb..6e67b7c 100644
--- a/lib/bitmask_attributes.rb
+++ b/lib/bitmask_attributes.rb
@@ -51,4 +51,6 @@ def reload(*)
   end
 end
 
-ActiveRecord::Base.send :include, BitmaskAttributes
+ActiveSupport.on_load(:active_record) do
+  ActiveRecord::Base.send :include, BitmaskAttributes
+end