Add link to lecture for Dist. Sys.

While Reliable Distributed Systems 1 is currently unavailable, the lectures for the course are still up on Youtube.

Author: waciumawanjohi

README.md

@@ -360,8 +360,8 @@ Courses | Duration | Effort | Prerequisites
 
 Courses | Duration | Effort | Prerequisites
 :-- | :--: | :--: | :--:
-[Reliable Distributed Systems, Part 1](https://www.edx.org/course/reliable-distributed-algorithms-part-1-kthx-id2203-1x) | 5 weeks | 5 hours/week | Scala, intermediate CS
-[Reliable Distributed Systems, Part 2](https://www.edx.org/course/reliable-distributed-algorithms-part-2-kthx-id2203-2x) | 5 weeks | 5 hours/week | Part 1
+[Reliable Distributed Systems, Part 1](https://www.edx.org/course/reliable-distributed-algorithms-part-1-kthx-id2203-1x) ([alt](https://www.youtube.com/watch?v=bPMOpxFMJUE&list=PLpeTtG9-RpWkQHiB_mAR9aftkuTluFxdX)) | 5 weeks | 5 hours/week | Scala, intermediate CS
+[Reliable Distributed Systems, Part 2](https://www.edx.org/course/reliable-distributed-algorithms-part-2-kthx-id2203-2x) ([alt](https://www.youtube.com/watch?v=jFCQ4hmMcus&list=PLx3mQFFeHPjndmQ0iP9j6C58b90hqGa0X&index=92)) | 5 weeks | 5 hours/week | Part 1
 [Electricity and Magnetism, Part 1](https://www.edx.org/course/electricity-magnetism-part-1-ricex-phys102-1x-0)<sup>1</sup> | 7 weeks | 8-10 hours/week | calculus, basic mechanics
 [Electricity and Magnetism, Part 2](https://www.edx.org/course/electricity-magnetism-part-2-ricex-phys102-2x-0) | 7 weeks | 8-10 hours/week | Electricity and Magnetism, Part 1
 [Computation Structures 1: Digital Circuits](https://www.edx.org/course/computation-structures-part-1-digital-mitx-6-004-1x-0) | 10 weeks | 6 hours/week | electricity, magnetism