gistfile1.rb

class Property < ActiveRecord::Base
  has_many :exclusions
  
  def excluded_on?(a_date)
    self.exclusions.each do |offering|
      return false if offering.start_date >= a_date && offering.end_date <= a_date
    end
    true
  end
end

class Exclusion < ActiveRecord::Base
  belongs_to :property
  validates_presence_of :start_date, :end_date
end