Ruby on rails "No route matches"

I am new to Rails and am just implementing some basic applications. Just starting on my second app and have run into what is a basic problem, but Google is yielding me nothing.

Getting this error:

No route matches {:controller=>"user", :action=>"admin_login"}

Here is my routes.rb

Blah::Application.routes.draw do
  resources :items, :cart, :user
end

Here is my applications.html.erb (the idea is this is a header of course, and I'm trying to create a link to 'login'. Right now it's just supposed to set the 'login' session variable to '1'.

<!DOCTYPE html>
<html>
<head>
  <title>Blah</title>
  <%= stylesheet_link_tag :all %>
  <%= javascript_include_tag :defaults %>
  <%= csrf_meta_tag %>
</head>
<body>

<div id="headerHolder">
    <div id="title">blah</div>
    <div id="menu">
        <div class ="menuItem">blog</div>
        <div class ="menuItem">
            <%= link_to "products",  :controller => "items", 
                                     :action => "index" %>
        </div>
        <div class ="menuItem">contact</div>    
        <div class="menuItem">
            <%= link_to "cart",  :controller => "cart", 
                                 :action => "index" %>
        </div>
        <div class="menuItem">
                <%= link_to_unless_current "admin", :controller => "user", 
                                                    :action => "admin_login" %>
        </div>
    </div>
</div>

<div id="content">
    <%= yield %>
</div>

</body>
</html>

And this is my user_controller.rb

class UserController < ApplicationController

  def index
  end

  def admin_login
    session[:login] = 1