ignore field name in errors

gistfile1.haml

# in your model
def self.full_message_fields
  [:field1, :field2] # these fields will display the full message
end

# inside your form
-if @group.errors.any?
    #error_explanation
      %ul
      - @group.errors.each do |attr, msg|
        - if @group.class.full_message_fields.include? attr
          %li= "#{attr} #{msg}"
        - else
          %li= msg