small concern that allows you to override the field names for validation messages

custom_field_names.rb

# small concern that allows you to override the field names for validation messages
#
# Example:
#
#   # without concern
#   class User < ActiveRecord::Base
#     validates :name, presence: true
#   end
#   # => "Name can't be blank"
#
#   # with concern
#   class User < ActiveRecord::Base
#     include CustomFieldNames
#     # use "My name" instead of "Name"
#     rename_fields :name => 'My name'
#
#     validates :name, presence: true
#   end
#   # => "My name can't be blank"
#
module CustomFieldNames
  extend ActiveSupport::Concern

  included do
    extend ClassMethods
    class_attribute(:_field_name_map){ Hash.new }
  end

  module ClassMethods
    # Example:
    #   rename_fields :column => 'New Name'
    def rename_fields(map = {})
      self._field_name_map = map.symbolize_keys
    end

    # override some error messages to use our custom column names
    def human_attribute_name(attribute, options = {})
      self._field_name_map[attribute.to_sym] || super
    end
  end
end