diff --git a/lib/dm-validations/validation_errors.rb b/lib/dm-validations/validation_errors.rb
index <HASH>..<HASH> 100644
--- a/lib/dm-validations/validation_errors.rb
+++ b/lib/dm-validations/validation_errors.rb
@@ -84,6 +84,17 @@ module DataMapper
         end
       end
 
+      # Return validation errors for a particular field name or an empty array
+      #
+      # This method is a necessary requirement for active_model compatibility.
+      #
+      # @param [Symbol] field_name the name of the field you want an error for
+      # @return [Array<Array<String>>]
+      #   array of validation errors or empty array, if there are no errors on given field
+      def [](field_name)
+        errors[field_name] ||= []
+      end
+
       # Return validation errors for a particular field_name.
       #
       # @param [Symbol] field_name the name of the field you want an error for
[dm-validations] Improved active_model compatibility

With this change, dm-validations is compatible with
active_model's requirements regarding the #errors and
the #valid? method.

The remaining aspects of of active_model compatibility
are handled inside the dm-active_model plugin.