title: present view controller on selecting tabbar item
body: <p>how to present view controller when tabbar item clicked.
  I just want to display as a popover .
  Using storyboard</p>
  
  <p>i found that solution but this is not working </p>
  
  <pre><code>  AddImage *yourViewController= (AddImage*)  [self.tabBarController.viewControllers objectAtIndex:3];
  
      CGFloat tabBarHeight = self.tabBarController.tabBar.bounds.size.height;
      CGRect rect = CGRectMake(0, 0, tabBarHeight, tabBarHeight);
      [AddImage presentPopoverFromRect:rect
                                                                               inView:self.tabBarController.tabBar
                                                             permittedArrowDirections:UIPopoverArrowDirectionDown animated:YES];
  </code></pre>