title: Enable back back swipe gesture when using custom navigation controller
body: <p>I've got a custom navigation controller declared as below. My problem is that once I implement this, the back swipe gesture to go back to previous stack (interactivepopgesturerecognizer) is not working. How can I enable it back? I've got a lot of view controller in my app. Thank You.</p>
  
  <pre><code>    #import "NavController.h"
  
      @interface NavController ()
      {
          BOOL shouldIgnorePushingViewControllers;
      }
  
      @end
  
      @implementation NavController
  
      -(instancetype)init {
          self = [super init];
          self.delegate=self;
  
          return self;
  
      }
  
      -(void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
      {
          if (!shouldIgnorePushingViewControllers)
          {
              [super pushViewController:viewController animated:animated];
          }
  
          shouldIgnorePushingViewControllers = YES;
      }
  
      - (void)didShowViewController:(UIViewController *)viewController animated:(BOOL)animated
      {
          shouldIgnorePushingViewControllers = NO;
      }
  
      @end
  </code></pre>