>一对一关联
表示一个模型可能只与另一个模型关联。为了使模型知道它与其他哪些模型关联，外键必需包含在记录中。、
http://imfly.github.io/sails-docs/concepts/ORM/Associations/OnetoOne.html
>一对多关联
http://imfly.github.io/sails-docs/concepts/ORM/Associations/OnetoMany.html
>多对多关联
http://imfly.github.io/sails-docs/concepts/ORM/Associations/ManytoMany.html