Added an extra link to 15-251 (#212)

README.md

@@ -626,7 +626,8 @@ Table of Contents
 - [Principles of Compiler Design - Swarthmore College](https://www.cs.swarthmore.edu/~jpolitz/cs75/s16/index.html)
 - [Undergrad Complexity Theory at CMU](https://www.youtube.com/playlist?list=PLm3J0oaFux3YL5vLXpzOyJiLtqLp6dCW2)
 - [Graduate Complexity Theory at CMU](https://www.youtube.com/playlist?list=PLm3J0oaFux3b8Gg1DdaJOzYNsaXYLAOKH)
-- [Great Ideas in Theoretical Computer Science at CMU](https://www.youtube.com/playlist?list=PLm3J0oaFux3aafQm568blS9blxtA_EWQv)
+- [Great Ideas in Theoretical Computer Science at CMU](https://www.youtube.com/playlist?list=PLm3J0oaFux3aafQm568blS9blxtA_EWQv) 
+  - [Another link](https://www.cs251.com/)
 - [Analysis of Boolean Functions at CMU](https://www.youtube.com/playlist?list=PLm3J0oaFux3YypJNaF6sRAf2zC1QzMuTA)
 - [Theoretical Computer Science (Bridging Course)(Tutorial) - SS 2015](http://ais.informatik.uni-freiburg.de/teaching/ss15/bridging/)
 - [Languages & Translators - UCLouvain LINFO2132](https://norswap.com/compilers/)