title: how to change shape of background of active link in nav of twitter bootstrap?
body: <p>I am using a Twitter Bootstrap at my web site and using Nav(Basic pills) as a navigation.</p>
  
  <p>When I click on list menu or hover effect the default behaviour is to show background's shape  is rectangle.</p>
  
  <p>Now my problem is I want to change that shape into my own customize shape.
  Please suggest me the right way to do this. </p>
  
  <p>Default shape is</p>
  
  <p><img src="https://i.stack.imgur.com/PMpPa.png" alt="enter image description here"></p>
  
  <p>and shape that I want is like</p>
  
  <p><img src="https://i.stack.imgur.com/H2xdC.png" alt="enter image description here"></p>