Add iOS content (#5829)

* add iOS content

* add GitHub article

* Update src/data/roadmaps/ios/content/functional-programming@Pj-hqRZUmwx1WhmTbLoFD.md

---------

Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

src/data/roadmaps/ios/content/functional-programming@Pj-hqRZUmwx1WhmTbLoFD.md

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-# Functional Programming
+# Functional Programming
+
+Functional programming is a style of programming where code is written using pure functions, avoiding changing state and mutable data. It emphasizes the use of mathematical functions to process data, which leads to more predictable and bug-resistant code. This approach helps in writing concise, readable, and testable code.
+
+Learn more from the following resources:
+
+- [@article@The Principles of Functional Programming](https://www.freecodecamp.org/news/the-principles-of-functional-programming/)
+- [@video@Functional programming - A general introduction](https://www.youtube.com/watch?v=8z_bUIl_uPo)
+- [@video@Intro to Swift for Functional Programmers](https://www.youtube.com/watch?v=rYC-TnKoi40)

src/data/roadmaps/ios/content/git@QifWR7WSJJTcTK2IfczxG.md

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-# Git
+# Git
+
+Git is a distributed version control system **(VCS)** used to track changes in source code during software development. It allows multiple developers to collaborate on a project by managing different versions of the code, enabling them to work on separate branches, merge changes, and keep a complete history of modifications.
+
+Learn more from the following resources:
+
+- [@official@Git Documentation](https://www.git-scm.com/)
+- [@video@Git in 100 Seconds](https://www.youtube.com/watch?v=hwP7WQkmECE)
+- [@article@An introduction to Git](https://www.freecodecamp.org/news/what-is-git-and-how-to-use-it-c341b049ae61/)

src/data/roadmaps/ios/content/github@U_xXGSFF5iibQ4VkzPAWf.md

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-# GitHub
+# GitHub
+
+GitHub is a web-based platform that uses Git for version control and collaboration. It provides a centralized repository for hosting and managing Git repositories, allowing developers to share their code, collaborate on projects, and track issues.
+
+Learn more from the following resources:
+
+- [@official@GitHub Docs](https://docs.github.com/en)
+- [@video@How to Use GitHub](https://www.youtube.com/watch?v=v_1iqtOnUMg)
+- [@article@What is GitHub](https://blog.hubspot.com/website/what-is-github-used-for)

src/data/roadmaps/ios/content/oop@FoqlB7xBIrV4yUp4ReBkw.md

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-# OOP
+# OOP
+
+Object-Oriented Programming **(OOP)** is a style where code is organized around "objects," which are instances of classes combining data and methods. It emphasizes encapsulation, abstraction, inheritance, and polymorphism, enabling modular, reusable, and maintainable code. OOP allows developers to model real-world entities and their interactions, making complex software design more intuitive and efficient.
+
+Learn more from the following resources:
+
+- [@video@Object-oriented Programming in 7 minutes](https://www.youtube.com/watch?v=pTB0EiLXUC8)
+- [@article@What is Object-Oriented Programming?](https://www.freecodecamp.org/news/what-is-object-oriented-programming/)