I have been learning Rails 3 from a video on Lynda.com, and it has been going well up until lately. What i'm trying to do currently is restrict access to certain pages unless a session is present where the user is authorized (has logged in). This is working correctly because when I try to access the pages that I want restricted, I get redirected to the login form. The problem comes up when I try to login. I put the correct username in, but when I put the password in, any password at all, it doesn't even need to be the correct one, I get an error page I made a user admin account for development purposes, and when I login I get this error:

NameError in AccessController#attempt_login
undefined local variable or method `salt' for #<AdminUser:0x41a6a68>

Application Trace:
app/models/admin_user.rb:62:in `password_match?'
app/models/admin_user.rb:52:in `authenticate'
app/controllers/access_controller.rb:19:in `attempt_login'

Now, I don't know a ton about debugging as of right now, but based on the trace the method attempt_login in the access controller is the following:

Code Ruby:
def attempt_login
    authorized_user = AdminUser.authenticate(params[:username], params[:password])
    if authorized_user
      session[:user_id] = authorized_user.id
      session[:username] = authorized_user.username
      flash[:notice] = "You are now logged in."
      redirect_to(:action => 'menu')
      flash[:notice] = "Invalid username/password combination."
      redirect_to(:action => 'login')

I don't know if there is an error in there that I am missing?

Anyway thanks in advance, and let me know if you need more of my code to find a solution because I am totally stuck at this point.