Defining Version Control Systems (#3157)

* Update readme.md

Definition and examples of Version Control Systems.

* Update content/roadmaps/117-flutter/content/104-version-control-systems/readme.md

* Update content/roadmaps/117-flutter/content/104-version-control-systems/readme.md

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

content/roadmaps/117-flutter/content/104-version-control-systems/readme.md

@@ -1 +1,9 @@
-# Version control systems
+# Version Control Systems
+
+Version control systems allow you to track changes to your codebase/files over time. They allow you to go back to some previous version of the codebase without any issues. Also, they help in collaborating with people working on the same code – if you’ve ever collaborated with other people on a project, you might already know the frustration of copying and merging the changes from someone else into your codebase; version control systems allow you to get rid of this issue.
+
+Visit the following resources to learn more:
+
+- [Version Control System Introduction](https://www.youtube.com/watch?v=zbKdDsNNOhg)
+- [Git & GitHub Crash Course For Beginners](https://www.youtube.com/watch?v=SWYqp7iY_Tc)
+- [Learn Git in 20 Minutes](https://youtu.be/Y9XZQO1n_7c?t=21)