Merge pull request #859 from byo-books/byo-2

Add the database, regex, and interpreter links from build-your-own.org.

README.md

@@ -134,6 +134,7 @@ It's a great way to learn.
 * [**Python**: _DBDB: Dog Bed Database_](http://aosabook.org/en/500L/dbdb-dog-bed-database.html)
 * [**Python**: _Write your own miniature Redis with Python_](http://charlesleifer.com/blog/building-a-simple-redis-server-with-python/)
 * [**C++**: _Build Your Own Redis from Scratch_](https://build-your-own.org/redis)
+* [**Golang**: _Build Your Own Database from Scratch: Persistence, Indexing, Concurrency_](https://build-your-own.org/database/)
 * [**Ruby**: _Build your own fast, persistent KV store in Ruby_](https://dinesh.wiki/posts/build-your-own-persistent-kv-store/)
 
 #### Build your own `Docker`
@@ -318,6 +319,7 @@ It's a great way to learn.
 * [**Python**: _How to Write a Lisp Interpreter in Python_](http://norvig.com/lispy.html)
 * [**Python**: _Let’s Build A Simple Interpreter_](https://ruslanspivak.com/lsbasi-part1/)
 * [**Python**: _Make Your Own Simple Interpreted Programming Language_](https://www.youtube.com/watch?v=dj9CBS3ikGA&list=PLZQftyCk7_SdoVexSmwy_tBgs7P0b97yD&index=1) [video]
+* [**Python**: _Build Your Own Interpreter/Compiler: The Pretty Laughable Compiler_](https://build-your-own.org/b2a/p0_intro)
 * [**Racket**: _Beautiful Racket: How to make your own programming languages with Racket_](https://beautifulracket.com/)
 * [**Ruby**: _A Compiler From Scratch_](https://www.destroyallsoftware.com/screencasts/catalog/a-compiler-from-scratch)
 * [**Ruby**: _Markdown compiler from scratch in Ruby_](https://blog.beezwax.net/2017/07/07/writing-a-markdown-compiler/)
@@ -334,6 +336,7 @@ It's a great way to learn.
 * [**JavaScript**: _How to implement regular expressions in functional javascript using derivatives_](http://dpk.io/dregs/toydregs)
 * [**JavaScript**: _Implementing a Regular Expression Engine_](https://deniskyashif.com/2019/02/17/implementing-a-regular-expression-engine/) 
 * [**Perl**: _How Regexes Work_](https://perl.plover.com/Regex/article.html)
+* [**Python**: _Build Your Own Regular Expression Engines: Backtracking, NFA, DFA_](https://build-your-own.org/b2a/r0_intro)
 * [**Scala**: _No Magic: Regular Expressions_](https://rcoh.svbtle.com/no-magic-regular-expressions)
 
 #### Build your own `Search Engine`