title: Devise not displaying error messge during an authentication failure?
body: <p>I was expecting a flash notice when authentication failures occurs in devise.  But get nothing during a authentication failure, just the page refreshes and remains still. 
  I didn't change any stuffs. The default devise installation itself is not displaying flash errors with invalid authentication attempt.  I just installed devise as a gem a tryed to uise it. Din't even change a word of the code that is generated.<br>
  May be I thought if is it due to some browser comparability issues.<br>
  But I get other mannually introduced flash messsages else working.   </p>
  
  <p>Any suggestions as to what may be broken.</p>
  
  <p>I'm using rails 3.0.1<br>
  <strong>* Update *</strong>  </p>
  
  <p>I'm getting failure messages for user registration(sign up) but not for failures messages of signing in.
  some googleing on this topic revealed that for sign up it expects:-<br>
    &lt;%= devise_error_messages! %>
  But for sign in it expects some other alert message tag to be referenced, but didn't get the exact info of what is that alert tag which i must use and wher to use ???</p>
  
  <p>Please provide some suggestions !!!<br>
  Thanks in advance.</p>