Ruby on Rails

Hello,

  

  I am trying to fetch instances details from amazon and trying to store in local mysql db. I am able to fetch all the details from amazon, but while storing the data in mysql i am getting the error undefined method `stringify_keys'  at two places [which ever gets executed first]

  

  Below is my code, can anyone please help me to resolve this error?  [ I marked error in red]

class Ec < ActiveRecord::Base

   attr_accessible :instance_id, :name, :public_ip_address, :availability_zone, :state, :created_at, :flavor_id, :account

   def sync

         properties = Array.new

         instance = Ec.new

         connection_dev = Fog::Compute.new({

           :provider                 => 'AWS',

           :aws_access_key_id        => '#######',

           :aws_secret_access_key    => ######'

       })

       dev_instances_list = connection_dev.servers.all

       

       dev_instances_list.each do | inst|

        begin

          instance[:instance_id] =  inst.id

          instance[:name] =   (inst.tags['Name'].to_s.empty?)? "NA" : inst.tags['Name']

          instance[:public_ip_address] =  inst.public_ip_address

          instance[:availability_zone] =  inst.availability_zone

          instance[:state] =  inst.state

          instance[:created_at] =  inst.created_at

          instance[:flavor_id] =  inst.flavor_id

          instance[:account] =  "abc"

          #instance.save

          properties.push(instance)

        rescue

            puts "exception"

        end

       end

      update_instance_details(properties)

   end

   def update_instance_details(properties)

       updated_list = Array.new

       to_store = Hash.new

       up = Ec.new

       Ec.find_each do |existing|

          to_store = properties.select{|a| a[:instance_id] == existing.instance_id}

          if(to_store.nil?)

            #someone has deleted this instance from amazon

            puts "Removing the record"

            existing.delete

          else

          #update existing record from amazon if there any changes

            Ec.update(existing.id, to_store)                  //Errror line