Rails tutorial will_paginate raises undefined_method total_pages

Question

Ive been stuck for a while now in the rails tutorial. Im in section 10.3, where we are supposed to add pagination. I have added the gem 'will-paginate' to my Gemfile, and this is the index view

<h1>All users</h1>
<%= will_paginate %>
<ul class="users">
<% @users.each do |user| %>
    <li>
        <%= gravatar_for user, :size => 30 %>
        <%= link_to user.name, user %>
    </li>
<% end %>
</ul>
<%= will_paginate %>

The server raises the following problem:

ActionView::Template::Error (undefined method `total_pages' for #<Array:0xa0283fc>):
    1: <h1>All users</h1>
    2: <%= will_paginate %>
    3: <ul class="users">
    4:  <% @users.each do |user| %>
    5:      <li>

I have been trying to search for it.. but none of the solutions to apparently similar issues worked. Any ideas?