[Generate] relationship --belongs-to fails if child model has non-canonical PK

[claudiopro]

Steps to reproduce

1. Create a model with a non-standard primary key e.g. Car, PK=registration
2. Create a standard model e.g. Person
3. Invoke the generator to create a 1-1 relationship:

$ emerails_generate relationship --belongs-to person car

Expected behavior

The generator can correctly create a foreign key column in the cars table.

Actual behavior

Error:

☠ Error (ALTER TABLE `cars` ADD `person_id` int(11) NULL DEFAULT NULL AFTER `id`, ADD INDEX (`person_id`);
ALTER TABLE `cars` ADD FOREIGN KEY (`person_id`) REFERENCES `people`(`id`) ON DELETE NO ACTION ON UPDATE NO ACTION;): Unknown column 'id' in 'cars'