def new
    @survey = Survey.find params[:survey_id]
    @questions = @survey.questions(:include => :answers).map{|q| q.answers.build}

    respond_to do |format|
      format.html # new.html.erb
      format.xml  { render :xml => @answer }
    end
  end

  def update
    @survey.find params[:id]
    @survey.update_attributes params[:survey]

    redirect_to wherever
  end


_form.html.haml
= form_for @survey do |f|
  - f.fields_for :questions do |qf|
    = qf.text_field :question
    - qf.fields_for :answers do |af|
      = af.text_field :answer
  .actions
  = f.submit