Ruby on Rails (notes for observers)

OBSERVERS

lib/inventory_init.rb
   ActiveRecord::Base.observers = [:item_observer,
 :item_supplier_observer]


config/environment.rb
   require 'inventory.init'
   config. load_path += %W(#RAILS_ROOT/app/observers)


class ItemObserver < ActiveRecord::Observer
   def before_create(record)
       #code here
   end
   def after_create(record)
       #code here
   end
end

def before_update(record)
   @status = record.status
end

def after_update(record)
   if  @status == record.status
       # Your code here.
   end
end

Ruby on Rails Find or Create

sample Code:
row = Category.find_or_create_by_name("General")
row = ItemSupplier.find_or_create_by_suplier_id(1,2)