models.rb

class Property < ActiveRecord::Base
  
  has_many :features
  has_many :ammenities, :through => :features
  
end

class Feature < ActiveRecord::Base
  
  belongs_to :ammenity
  belongs_to :property
  
end

class Ammenity < ActiveRecord::Base
  
  has_many :features
  has_many :properties, :through => :features
  
end