title: How to apply percentage discount to whole cart total in Magento?
body: <p>I have a issue like, I have to create a promotion rule which gives percentage total on cart total.
  Currently Magneto offers promotion rule on cart per item. But I have different scenario like </p>
  
  <pre><code>cart item total+extra fee = cart total - percentage discount
  </code></pre>
  
  <p>Current Magento rule calculates like</p>
  
  <pre><code>cart item total = cart total - percentage discount
  </code></pre>
  
  <p>I need this to implement with coupon code only.</p>
  
  <p>Help will be appreciated, 
  Thank You</p>