摘要：
很基础，但是却搞很久，在这里总结一下。class User < ActiveRecord::Base has_many :borrows has_many :books, :through => :borrowsendclass Book < ActiveRecord::Base has_many :borrows has_many :users, :through => :borrowsendclass Borrow < ActiveRecord::Base belongs_to :user belongs_to :bookend非常基础的多对多关系模型，需要注 阅读全文
