module ActiveRecord::AttributeMethods::Write

def attribute=(attribute_name, value)
  write_attribute(attribute_name, value)
end

def type_cast_attribute_for_write(column, value)
  return value unless column
  column.type_cast_for_write value
end

def write_attribute(attr_name, value)
  attr_name = attr_name.to_s
  attr_name = self.class.primary_key if attr_name == 'id' && self.class.primary_key
  @attributes_cache.delete(attr_name)
  column = column_for_attribute(attr_name)
  # If we're dealing with a binary column, write the data to the cache
  # so we don't attempt to typecast multiple times.
  if column && column.binary?
    @attributes_cache[attr_name] = value
  end
  if column || @attributes.has_key?(attr_name)
    @attributes[attr_name] = type_cast_attribute_for_write(column, value)
  else
    raise ActiveModel::MissingAttributeError, "can't write unknown attribute `#{attr_name}'"
  end
end