title: Devise not displaying login error messages
body: <p>I am using devise on my application and i am not getting error messages when login fails.</p>
  
  <p>I've flash[:notice] and flash[:alert] on the login page.</p>
  
  <p>I tried a lot of things and when i remove 'protect_from_forgery' from application controller i get the error messages.</p>
  
  <p>Also i am using Cancan on my application, can it be any issue from it? Any ideas?</p>
  
  <p>Thanks</p>