title: chef attributes set to another attribute
body: <p>In my attribute file i have </p>
  
  <pre><code>default['appid']['user'] = 'sysUserA'
  </code></pre>
  
  <p>Now I also want to set the same attribute to another one for a wrapper cookbook.
  So I add another line so that with reference to first. </p>
  
  <pre><code>default['appid']['user'] = 'sysUserA'
  default['service']['user'] = node['appid']['user']
  </code></pre>
  
  <p>The idea is to not update the same attribute at multiple locations. Is it the best way to do it, given that <strong>default['appid']['user']</strong> and <strong>default['service']['user']</strong>  definitely needs to be defined. Or this needs to be taken tot he recipe.</p>
  
  <p>Thanks</p>