class School
  include Mongoid::Document
  #references_one :human
  referenced_in :human, :inverse_of => :schools
  referenced_in :alien, :class_name => 'Human', :foreign_key => :alien_id
  # referenced_in :middle, :class_name => 'Human'
  # referenced_in :high, :class_name => 'Human'
  field :name
end

class Human
  include Mongoid::Document
  field :name
  references_many :schools, :inverse_of => :human
  references_many :alien_schools, :class_name => 'School', :inverse_of => :alien, :foreign_key => :alien_id

  #references_many :middle, :stored_as => :array, :inverse_of => :middle, :class_name => 'School'
  #references_many :weekend_gyms, :inverse_of => :gym
  #references_many :preferences, :stored_as => :array, :inverse_of => :people
end