title: Extend class method
body: <p>This code is working fine.</p>
  
  <pre><code>class ArInvHeader &lt; ActiveRecord
  
    HUMANIZED_ATTRIBUTES = {
      :shipto_customer_address =&gt; _("Ship to customer address ")
    }
  
    def self.human_attribute_name(attr,options={})
      HUMANIZED_ATTRIBUTES[attr.to_sym] || super
    end
  
  end
  </code></pre>
  
  <p>I want to put this method in common file and use it in every model.</p>
  
  <pre><code>def self.human_attribute_name(attr,options={})
    HUMANIZED_ATTRIBUTES[attr.to_sym] || super
  end
  </code></pre>
  
  <p>How may i do this ?</p>