title: Code igniter how to add constant in config folder
body: <p>This is how, code igniter folder path is</p>
  
  <pre><code>application-&gt;config
  system
  x -&gt; y -&gt; z
  </code></pre>
  
  <p>I want to create a constant for folder x,y,z.</p>
  
  <p>How do I do this in code igniter ?</p>