title: Changing devise flash messages from notice to error
body: <p>I know that you can override the default devise controllers and I did so for the Registrations and Sessions Controller. I know that you can also change the text for the flash messages in devise under locale. However, I am not sure how to change the type of flash message showing for the sessions controller when there is an invalid combination of username and password. </p>
  
  <p>The create method looks like </p>
  
  <pre><code>def create
    self.resource = warden.authenticate!(auth_options)
    set_flash_message(:notice, :signed_in) if is_navigational_format?
    sign_in(resource_name, resource)
    respond_with resource, :location =&gt; after_sign_in_path_for(resource)
  end
  </code></pre>
  
  <p>I suspect that the validation is done during the follow call</p>
  
  <pre><code>warden.authenticate!(auth_options) 
  </code></pre>
  
  <p>But this is where I am not sure how to overwrite that in my app. </p>
  
  <p>Also, I think it is a complex override for such a simple use case of changing the color of a flash notice.</p>
  
  <p>Any insights would be much appreciated. </p>
  
  <p>Thanks!
  Nick</p>