title: undefined method `paginate' for Array on Rails 3 with mongoid
body: <p>Trying to use <a href="https://github.com/mislav/will_paginate" rel="nofollow">will_paginate gem</a>.</p>
  
  <p>My Gem file has:</p>
  
  <pre><code>gem 'will_paginate', '~&gt; 3.0.0'
  </code></pre>
  
  <p>My orders_controllers.rb:</p>
  
  <pre><code>def index
      @orders = Order.all.paginate(:page =&gt; params[:page], :per_page =&gt; 20)
  
      respond_to do |format|
        format.html # index.html.erb
        format.json { render json: @orders }
      end
    end
  </code></pre>
  
  <p>On my index.html.erb I've put:</p>
  
  <pre><code>&lt;%= will_paginate @orders %&gt;
  </code></pre>
  
  <p>Error:</p>
  
  <pre><code>NoMethodError in OrdersController#index
  
  undefined method `paginate' for #&lt;Array:0x007f79a1be62f8&gt;
  Rails.root: /home/askar/Dropbox/rails_studio/somics
  
  Application Trace | Framework Trace | Full Trace
  app/controllers/orders_controller.rb:5:in `index'
  </code></pre>
  
  <p>I now there's kaminari gem for pagination, but I want to know about will_paginate.</p>