add beam wisdoms under erlang (#3881)

* add beam wisdoms

check_urls=free-programming-books.md
Signed-off-by: Ntechgaun <coolsamar207@gmail.com>

* add the beam book

added the beam book also called the erlang runtime system book
check_urls=free-programming-books.md
Signed-off-by: Ntechgaun <coolsamar207@gmail.com>

free-programming-books.md

@@ -1247,6 +1247,7 @@ Kerridge (PDF) (email address *requested*, not required)
 
 ### Erlang
 
+* [BEAM Wisdoms](http://beam-wisdoms.clau.se/en/latest/) (HTML)
 * [Concurrent Programming in ERLANG](http://www.erlang.org/download/erlang-book-part1.pdf) (PDF)
 * [Erlang Handbook](https://github.com/esl/erlang-handbook/raw/master/output/ErlangHandbook.pdf) (PDF)
 * [Erlang Programming](https://en.wikibooks.org/wiki/Erlang_Programming) - Wikibooks (HTML)
@@ -1254,6 +1255,7 @@ Kerridge (PDF) (email address *requested*, not required)
 * [Learn You Some Erlang For Great Good](http://learnyousomeerlang.com) - Frederic Trottier-Hebert
 * [Making reliable distributed systems in the presence of software errors](http://www.erlang.org/download/armstrong_thesis_2003.pdf) - Joe Armstrong (PDF)
 * [Stuff Goes Bad: Erlang in Anger](https://www.erlang-in-anger.com) - Fred Herbert (PDF)
+* [The BEAM Book](https://blog.stenmans.org/theBeamBook) (HTML)
 
 
 ### ESP8266