gistfile1.rb

class Employee < ActiveRecord::Base
  has_many :events
  
  def self.in_on_date(date)
    Event.where(:date => date).map{ |e| e.employee.name }.uniq
  end
  
  def book_in_date!(date)
    self.events.build(:date => date)
    self.save!
  end
  
end