composed_of(part_id, options = {})
Instance Public methods
Adds reader and writer methods for manipulating a value object:
composed_of :address adds address and
address=(new_address) methods.
Options are:
:class_name - Specifies the class name of the association. Use
it only if that name can't be inferred from the part id. So
composed_of :address will by default be linked to the Address class, but if the real class name is
CompanyAddress, you'll have to specify it with this option