Merge pull request theanalyst#39 from qkniep/master

Fix broken link for Andrew Tanenbaum's book

README.md

@@ -14,7 +14,7 @@ Read things here before you start.
 
 ## Books
 - [Distributed Systems for fun and profit](http:https://book.mixu.net/distsys/single-page.html) [Free]
-- [Distributed Systems Principles and Paradigms, Andrew Tanenbaum](https://www.distributed-systems.net/index.php/books/distributed-systems-3rd-edition-2017/ds3-sneak-preview/) [Free with registration]
+- [Distributed Systems Principles and Paradigms, Andrew Tanenbaum](https://www.distributed-systems.net/index.php/books/ds3/) [Free with registration]
 - [Scalable Web Architecture and Distributed Systems](http:https://www.aosabook.org/en/distsys.html) [Free]
 - [Principles of Distributed Systems](http:https://dcg.ethz.ch/lectures/podc_allstars/lecture/podc.pdf) [Free] [ETH Zurich University]
 - [Making reliable distributed systems in the presence of software errors](http:https://www.erlang.org/download/armstrong_thesis_2003.pdf), [Free] Joe Amstrong's (Author of Erlang) PhD thesis