Hi dear community,
I created a survey app which has questions and answers as radio buttons. So firstly i asked onstackoverflow(click-here). A good guy helped me but there is some issue in form.     This my survey_controller:
     def new_response
    @survey = Survey.find(params[:id])
    @response = @survey.responses.build
    # now, the tricky part, you have to build the Answer objects so you can use the nested form later
    @survey.questions.each do |q|
      @response.answers.build question: q
    end
  end
def create_response
  @survey = Survey.find(params[:id])
  @response = @survey.build(response_params)
  @response.user = current_user
  @response.save
end
Here is my create_response form:
  = form_for @response, url: create_response_survey_path(@survey) do |f|
      - # you can iterate over all the answers already initialized
      = f.fields_for :answers do |ff|
         - # get the question from the current answer to show the title and options and a hidden_field with the      question id
        - q = ff.object.question
    = q.title
    = ff.hidden_field :question_id
    - # add the radios for each options for the question
    - q.options.each do |option|
      = label_tag do
        = ff.radio_button :option_id, option.id
        = option.title
  = f.submit 'Send'
My routes file:
Rails.application.routes.draw do
  devise_for :users
  	resources :surveys do 
    member do
      get :new_response
      get :create_response 
    end
        end
  root 'surveys#index'
  end
It is showing error below when i try open the response form:
    create_response.html.haml
    undefined method `question' for nil:NilClass
    - q = ff.object.question
This is the repository link if you need check: Repository - Link
Thanks for all helps.