guest_token = Rails.cache.fetch('guest_access_token', :expires_in => ENV['MEMCACHE_EXPIRY'].to_i.minute) do
      client = Restforce.new :username => ENV['SFDC_PUBLIC_USERNAME'],
        :password       => ENV['SFDC_PUBLIC_PASSWORD'],
        :client_id      => ENV['SFDC_CLIENT_ID'],
        :client_secret  => ENV['SFDC_CLIENT_SECRET'],