[Rails]{ActiveRecord][PostgreSQL] sort columns

attributes.rb

#
# config/initializers/extensions/active_record/attributes.rb
# https://github.com/rails/rails/blob/4-2-stable/activerecord/lib/active_record/attributes.rb
#
module ActiveRecord #:nodoc:
  module Attributes # :nodoc:
    module ClassMethods

      # Overriding method
      def columns
        # @columns ||= add_user_provided_columns(connection.schema_cache.columns(table_name)) #Original
        @columns ||= add_user_provided_columns(connection.schema_cache.columns(table_name).sort!(&scheme_comparator))
      end

      private

        # New method
        def scheme_comparator
          lambda do |a,b|
            a.name.end_with?("_at") ?
              (b.name.end_with?("_at") ? 0 : 1) :
              (b.name.end_with?("_at") ? -1 : 0)
          end
        end

    end
  end
end