title: Rails flash :notice doesn't work
body: <p>I have this code :</p>
  
  <pre><code>def create
    login(params[:email], params[:password])
  
    if current_user
      flash[:notice] = "Welcome back #{current_user.email}"
      return redirect_to_first_page
    else
      flash[:notice] = "Email or password is wrong. Try again !"
      redirect_to root_url
    end
  end
  </code></pre>
  
  <p>when the login is successful the flash is set and the redirect to the first page is made.
  This part is working. The second part is not setting the flash notice message. Then when the page is displayed no message from flash is show. What is different i've try to have </p>
  
  <pre><code>return redirect_to root_url
  </code></pre>
  
  <p>but nothing still not showing anything.
  In my controller i have a helper like flash_notice all it does is return flash[:notice].
  This is because the flash is always empty in a view but accessible in controller. 
  In the view i have just one line :</p>
  
  <pre><code>&lt;%= flash_notice %&gt;
  </code></pre>
  
  <p>I'm using rails 3.1</p>