First of all in has_many class name should be in plural: has_many :choices And you should add attr_accessible poll_id or choice_ids for Model from which you want to edit this association. Or just delete all attr_accessible for first try.

gistfile1.rb

class Poll < ActiveRecord::Base
  attr_accessible :published, :title, choice_ids

  validates :published, :presence => true
  validates :title, :presence => true, :length => { :minimum => 10 }

  has_many :choices, :dependent => :destroy
end


class Choice < ActiveRecord::Base
  belongs_to :poll
  attr_accessible :choice_text, :votes, :poll_id

  validates :choice_text, :presence => true

end