moved code question into thread management

Author: onthecodepath

README.md

@@ -15,7 +15,6 @@ Use the Table of Contents to practice and test your knowledge. It doesn't show t
     - What is the delegation pattern?
     - What is MVC?
     - What is MVVM?
-- [Code Questions](https://github.com/onthecodepath/iOS-Interview-Questions#code-questions)
 - [Core Data](https://github.com/onthecodepath/iOS-Interview-Questions#core-data)
     - What is Core Data?
     - When would you use Core Data over NSUserDefault?
@@ -87,37 +86,6 @@ MVVM is an augmented version of MVC where the presentation logic is moved out of
 
 A common occurence in MVC is where you have a massive-view-controller (some joke this is what MVC stands for). In order to shrink the size of your view controller and make the logic and readibility of your code easier to follow along, the MVVM will be used. 
 
-## Code Questions
-
-#### Spot the bug that occurs in the code:
-
-```
-@interface MyCustomController : UIViewController  
-
-@property (strong, nonatomic) UILabel *alert;  
-
-@end  
-
-@implementation MyCustomController  
-
-- (void)viewDidLoad {
-  CGRect frame = CGRectMake(100, 100, 100, 50);
-  self.alert = [[UILabel alloc] initWithFrame:frame];
-  self.alert.text = @"Please wait...";
-  [self.view addSubview:self.alert];
-  dispatch_async(
-    dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),
-    ^{
-      sleep(10);
-      self.alert.text = @"Waiting over";
-      }
-    ); 
-}  
-```
-
-All UI updates must be performed on the main thread. Global dispatch queues do not make any guarantees so code should be modified to run the UI update on the main thread.
-
-
 ## Core Data
 
 #### What is Core Data?
@@ -271,6 +239,34 @@ GCD stands for Grand Central Dispatch. According to [Ray Wenderlich](https://www
 
 Tasks executed *serially* are executed one at a time while tasks that are executed *concurrently* may be executed at the same time.
 
+#### Spot the bug that occurs in the code:
+
+```
+@interface MyCustomController : UIViewController  
+
+@property (strong, nonatomic) UILabel *alert;  
+
+@end  
+
+@implementation MyCustomController  
+
+- (void)viewDidLoad {
+  CGRect frame = CGRectMake(100, 100, 100, 50);
+  self.alert = [[UILabel alloc] initWithFrame:frame];
+  self.alert.text = @"Please wait...";
+  [self.view addSubview:self.alert];
+  dispatch_async(
+    dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),
+    ^{
+      sleep(10);
+      self.alert.text = @"Waiting over";
+    }
+  ); 
+}  
+```
+
+All UI updates must be performed on the main thread. Global dispatch queues do not make any guarantees so code should be modified to run the UI update on the main thread. 
+
 ## Unit Testing
 
 #### What is the purpose of unit/UI testing? What are the benefits?