title: Adding Prefix Match to pg_search
body: <p>I am following <a href="http://railscasts.com/episodes/343-full-text-search-in-postgresql" rel="nofollow">this</a> Railscasts episode. </p>
  
  <p>If I search "Kerber" it does return the right article. 
  But if I search "Ke" it does not returns the same article. </p>
  
  <p>There's a way to fix this?</p>
  
  <pre><code>class Item &lt; ActiveRecord::Base
    include PgSearch
    pg_search_scope :search, against: [:description, :about, :link, :twitterhandle, :builtby],
    using: {tsearch: {dictionary: "english"}}
  
    def self.text_search(query)
      if query.present?
        search(query)
      else
        scoped
      end
    end
  </code></pre>