title: Rails - Devise - Error messages when signing in?
body: <p>How can I make <strong>f.error_messages</strong> work here, or should I use flashes?<br>
  If so, what should override in the sessions_controller?</p>
  
  <pre><code>&lt;h2&gt;Create an account&lt;/h2&gt;    
  &lt;% form_for resource_name, resource, :url =&gt; registration_path(resource_name) do |f| %&gt;
    &lt;%= f.error_messages %&gt;
    &lt;p&gt;
      &lt;%= f.label :email %&gt;&lt;br /&gt;
      &lt;%= f.text_field :email, :class =&gt; :big %&gt;
    &lt;/p&gt;
    &lt;p&gt;
      &lt;%= f.label :password %&gt;&lt;br /&gt;
      &lt;%= f.password_field :password, :class =&gt; :big %&gt;
    &lt;/p&gt;
    &lt;p&gt;
      &lt;%= f.label :password_confirmation %&gt;&lt;br /&gt;
      &lt;%= f.password_field :password_confirmation, :class =&gt; :big %&gt;
    &lt;/p&gt;
  
    &lt;p&gt;&lt;%= f.submit "Create", :class =&gt; :submit %&gt;&lt;/p&gt;
  &lt;% end %&gt;
  </code></pre>
  
  <p>PS. <strong>f.error_messages</strong> for Creating an account works totally fine.</p>