How does mongoid know to use plural name of a model when using references? -

i reading mongoid link, , came this:

class person   include mongoid::document   has_many :posts end  class post   include mongoid::document   field :title, type: string   belongs_to :person end 

how mongoid know has_many :posts refers post class? same if has_many :post?

as shows in current mongoid documentation, mongoid uses activesupport::inflector translate between singular , plural model , table names.