title: Uninitialized constant controller name
body: <p>In <code>routes.rb</code>, I used <code>resources nicknames</code>. In <code>nickname_controller</code>, I did:  </p>
  
  <pre><code>def index
      @nick_name = current_user.nicknames.build
      @nick_names = current_user.nicknames.all
    end
  
  def create
      @nick_name = current_user.nicknames.build(nn_create_param)
      if @nick_name.save
        flash[:success]= 'Name created'
        redirect_to nickname_path
      else
        flash[:danger]= "Name can't be created"
        redirect_to nickname_path
      end
    end
  </code></pre>
  
  <p>In index view file,</p>
  
  <pre><code>&lt;%= form_for @nick_name do |f| %&gt;
      &lt;%= f.text_field :nickname %&gt;
      &lt;%= f.submit 'Submit' %&gt;
  &lt;% end %&gt;
  </code></pre>
  
  <p>When I submit the form, it says <code>uninitialized constant NicknamesController</code>.</p>
  
  <p>Can anyone tell me where the problem is?</p>