title: NoMethodError in Polls#new -- undefined method `polls' for nil:NilClass
body: <p>Hello I have to develop a GoogleForm like application i already developed Forms/Questions/Answers and now i have to make my forms 'answerable' so I created a model Poll (a Form has_many polls and a poll belongs to a form). I Have this mistake <a href="https://projet.../formulaires/131/polls/new" rel="nofollow noreferrer">https://projet.../formulaires/131/polls/new</a>  and I don't understand how to handle it .</p>
  
  <p>My routes.rb :</p>
  
  <pre><code>  resources :formulaires do
       resources :polls
    end
  </code></pre>
  
  <p>My polls_controller :</p>
  
  <pre><code>def index
      @polls = @formulaire.polls.order("created_at DESC")
  end
  
  def show
  end
  
  def new
    @poll = Poll.new
  
  end
  
  def create
      @poll = @formulaire.poll.new(poll_params)
      @polls = @formulaire.polls.order("created_at DESC")
  
      if @poll.save
         redirect_to formulaire_polls_path(@formulaire)
      end
  end
  
  def poll_params
    params.require(:poll).permit(:formulaire_id, :question_id, :answer_id, :nom) 
  end
  
  end
  </code></pre>
  
  <p>And my polls/_form view to test it :</p>
  
  <pre><code>  &lt;%= form_for([@formulaire, @formulaire.polls.new]) do |f| %&gt;
  
  &lt;h2&gt; Test&lt;/h2&gt;
    &lt;%= f.label :nom %&gt;
    &lt;%= f.submit %&gt;
  &lt;% end %&gt;
  </code></pre>