Couch Rest Model Doubt

Hello Guys,

I am using couch-rest model gem and below is my snippet code.

class S
  include CouchRest::Model::Embeddable
  property :s1, String
  property :s2, String
end

class P < CouchRest::Model::Base
  property :name, String
  property :xx, [S]
end

p =P.new
p.xx << S.new(s1: "S1 EXISTS")
p.xx << S.new(s2: "S2 EXISTS")
p.save

Now my doubt is when i do p.save "null" get stored in the couchdb, which
I dont want. If i don't use array, then null gets auto deleted , I want
the same feature for the array as well.

Can you please suggest something?

Attachments:
http://www.ruby-forum.com/attachment/10784/Screen_Shot_2015-05-15_at_7.37.03_pm.png