title: Creating a View Controller that only appears on first app open
body: <p>I am creating a View Controller that only appears the first time the user opens the app. I had it working by just pushing the welcome view controller, but then I couldn't get it to push the normalViewController when the user was done in the welcomeViewController. I then then tried to set the welcomeViewController as the rootViewController. This still shows the welcomeScreen, but all of the buttons on it do not work. If any one knows how to fix this or a better way to create a welcomeViewController, it would be very much appreciated. Here is the code I am using to show the rootViewController</p>
  
  <pre><code>if ([[NSUserDefaults standardUserDefaults] boolForKey:@"TermsAccepted"]){
          NSLog(@"Second time opening the app");
      }
      else{
          WelcomeViewController *welcomeViewController = [[WelcomeViewController alloc] init];
          [[UIApplication sharedApplication] keyWindow].rootViewController = welcomeViewController;
      }
  </code></pre>
  
  <p>To create the UITabBar -</p>
  
  <pre><code>self.tabBarController = [[UITabBarController alloc] init];
  [[UITabBar appearance] setTintColor:[UIColor redColor]];
  
  
  // FeedViewController
  feedViewController=[[FeedViewController alloc] init];
  feedViewController.tabBarItem.image=[UIImage imageNamed:@"Describe Home_Icon_NormalArtboard-1"];
  feedViewController.title = @"Timeline";
  feedViewController.tabBarItem.title = nil;
  
  //TodayViewController
  TodayViewController *todayViewController = [[TodayViewController alloc] init];
  todayViewController.tabBarItem.image = [UIImage imageNamed:@"Today_Icon"];
  todayViewController.title = @"Today";
  todayViewController.tabBarItem.title = nil;
  
  //CreateViewController
  self.createViewController = [[CreateViewController alloc] init];
  self.createViewController.tabBarItem.image = [UIImage imageNamed:@"Create_Icon"];
  self.createViewController.title = @"Create";
  self.createViewController.tabBarItem.title = nil;
  
  //AlertViewController
  AlertsViewController *alertsViewController = [[AlertsViewController alloc] init];
  alertsViewController.tabBarItem.image=[UIImage imageNamed:@"Alerts_IconArtboard-1"];
  alertsViewController.title=@"Alerts";
  alertsViewController.tabBarItem.title = nil;
  
  //ProfileViewController
  ProfileViewController *profileViewController = [[ProfileViewController alloc] init];
  profileViewController.tabBarItem.image=[UIImage imageNamed:@"Profile_IconArtboard-1"];
  profileViewController.title=@"Profile";
  profileViewController.tabBarItem.title = nil;
  
  NSMutableArray *tabBarViewControllers = [[NSMutableArray alloc] initWithCapacity:2];
  
  self.tabBarController = [[UITabBarController alloc] init];
  
  
  UINavigationController *feedNavigationController = [[UINavigationController alloc] initWithRootViewController:feedViewController];
  [tabBarViewControllers addObject:feedNavigationController];
  feedNavigationController = nil;
  
  UINavigationController *todayNavigationController = [[UINavigationController alloc] initWithRootViewController:todayViewController];
  [tabBarViewControllers addObject:todayNavigationController];
  todayNavigationController = nil;
  
  UINavigationController *createNavigationController = [[UINavigationController alloc] initWithRootViewController:self.createViewController];
  [tabBarViewControllers addObject:createNavigationController];
  createNavigationController = nil;
  
  UINavigationController *alertsNavigationController = [[UINavigationController alloc] initWithRootViewController:alertsViewController];
  [tabBarViewControllers addObject:alertsNavigationController];
  alertsNavigationController = nil;
  
  UINavigationController *profileNavigationController = [[UINavigationController alloc] initWithRootViewController:profileViewController];
  [tabBarViewControllers addObject:profileNavigationController];
  profileNavigationController = nil;
  
  self.tabBarController.viewControllers = tabBarViewControllers;
  tabBarViewControllers = nil;
  
  [self.window addSubview:self.tabBarController.view];
  </code></pre>