title: how to output a specific category
body: <p>I have a rails 3 blog app which have article and category in <code>has_many</code> and <code>belongs_to association</code>,  i have a lot of category like sport news , entertaiment news etc but i want on my views only sportnews to show, i mean articles that has the category of sport to show and i want it to show on my application.html.erb</p>
  
  <pre><code>class Category &lt; ActiveRecord::Base
    has_many :registrations
    has_one  :payment
    attr_accessible :content, :name, :image, :description
  
     mount_uploader :image, ImageUploader
  
  end
  </code></pre>