GCD and Math

https://www.raywenderlich.com/79149/grand-central-dispatch-tutorial-swift-part-1

https://developer.apple.com/videos/play/wwdc2016/720/

https://github.com/SVProgressHUD/SVProgressHUD

You should do the following:

1. Create a new branch from develop called feature/gcd
2. Connect a new library SVProgressHUD via CocoaPods.
3. Add a new button to OrganizationInfoViewController called “Calculate 100000th Fibonacci number”. It should calculate 100000th Fibonacci number in a background queue (global queue). Upon completion it should output the result in an UIAlertController. SVProgressHUD should be shown during calculation.
4. Create a pull request.

You should be able to answer the following questions:

• What is GCD used for?
• What is main queue?
• What is the difference between sync and async?
• Can UI be changed in global queue?