title: How can I simply verify that a username and password are correct with Devise and Rails 3
body: <p>I am using <code>Devise</code> and <code>Rails 3</code>.</p>
  
  <p>I want to call a function that will simply verify that a user's <code>username</code> and password combination is correct without actually logging in that user. Is there some way I can accomplish something like this with Devise:</p>
  
  <pre><code>User.authenticate(params[:username], params[:password])
  </code></pre>