Add Os and General KnowKnowledge content at backend roadmap (#998)

* Add Os and General KnowKnowledge content at backend roadmap

* Update content/roadmaps/101-backend/content/102-os-general-knowledge/readme.md

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

content/roadmaps/101-backend/content/102-os-general-knowledge/readme.md

@@ -1 +1,8 @@
 # General Knowledge
+
+Operating System is a program that manages a computer’s resources, especially the allocation of those resources among other programs. Typical resources include the central processing unit (CPU), computer memory, file storage, input/output (I/O) devices, and network connections.
+
+<ResourceGroupTitle>Free Content</ResourceGroupTitle>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://edu.gcfglobal.org/en/computerbasics/understanding-operating-systems/1/'>What is an operating system?</BadgeLink>
+<BadgeLink badgeText='Watch' href='https://www.youtube.com/watch?v=26QPDBe-NB8&ab_channel=CrashCourse'>Operating Systems: Crash Course Computer Science #18</BadgeLink>
+<BadgeLink badgeText='Watch' href='https://www.youtube.com/watch?v=vBURTt97EkA&list=PL9hkZBQk8d1zEGbY7ShWCZ2n1gtxqkRrS&index=1'>Introduction to Operating System</BadgeLink>