title: Rails3 Active Admin - How to filter only records that meet all checked items in collection
body: <p>I have a one-to-many associaton of user to network model. The relevant parts of my schema information is as follows.</p>
  
  <pre><code># == Schema Information      
  # Table name: users
  #
  #  id                     :integer         not null, primary key
  #  name                   :string(255)
  
  #
  # Table name: networks
  #
  #  id         :integer         not null, primary key
  #  user_id    :integer
  #  uid        :string(255)
  #  name   :string(255)
  #  pub_url    :string(255)
  </code></pre>
  
  <p>I want to filter out users who have specific multiple networks using the name property of the network model. For example if I check facebook and foursquare as filters, I want to get back users who have connected both facebook and foursquare. My current implementation is to pass an array containing the names of networks a user can add as displayed below.</p>
  
  <pre><code>filter :networks_name, :as =&gt; :check_boxes,
  :collection =&gt; %w(facebook twitter foursquare linkedin)
  </code></pre>
  
  <p>This however uses an OR condition for the filters which retrieves users with any of the checked items. What I actually want to get is users who meet all the checked items.
  What's the right way of achieving this?</p>