* Add "What I Wish I Knew When Learning Haskell"
Follow up #3173.
* Update free-programming-books-zh.md
Follow up #3330.
* added competitive programming link
Follow up #3398.
* Add "Symfony 5: The Fast Track" book (en)
* Add "Symfony 5: The Fast Track" book (es)
* Add "Symfony 5: The Fast Track" book (de)
* Add "Symfony 5: The Fast Track" book (ar)
* Add "Symfony 5: The Fast Track" book (fa)
* Add "Symfony 5: The Fast Track" book (ja)
* Add "Symfony 5: The Fast Track" book (ru)
* Add "Symfony 5: The Fast Track" book (it)
* Add "Symfony 5: The Fast Track" book (nl)
* Add "Symfony 5: The Fast Track" book (pl)
* Add "Symfony 5: The Fast Track" book (pt_BR)
* Add "Symfony 5: The Fast Track" book (ro)
* Add "Symfony 5: The Fast Track" book (zh_CN)
* Add "Symfony 5: The Fast Track" book (fr)
* Remove redundant line breaks
* Format desc of zh version programming books base on CONTRIBUTING-zh.
* optimize zh version book comments.
* Fix Travis CI check.
* Commit update for suggestion of [zhongjiajie]
* Add Excel-vba Ebook repo.
* Add VBA Eboob Repo. and fix incorrect menu link.
* fix Wrong format line
* Fix incorrect markdown syntax.
* Refactor DB and Javascript menu ZH version md file.
Move 'MySQL, NoSQL, PostgreSQL' under menu: Language Agnostic(语言相关),
Delete a book link of [Google JSON 风格指南], it's a multiple repo. with [JSON 风格指南], 2 link is point to the same one page.
* Delete multiple ebook link
D1. [Redis 设计与实现](http://redisbook.com), wiich is the same as menu: NoSQL -> [Redis 设计与实现](http://redisbook.com)
D2. [The Little MongoDB Book 中文版](https://github.com/justinyhuang/the-little-mongodb-book-cn) wiich is the same as menu: NoSQL -> [The Little MongoDB Book](https://github.com/justinyhuang/the-little-mongodb-book-cn/blob/master/mongodb.md)
* Update comments description.
* remove multiple ebook link
* Fix machine chek issue(fix mistake link location of PostgreSQL)
* FIX machine checking [Do not use headings with similar content (544:1)]
* Fix machine checking [359:1-361:78 warning Alphabetical ordering: swap l.361 and l.360 alphabetize-lists]
* Replace homepage with GitHub repository link
problem-sets-competitive-programming.md: Replace homepage
link of problembook with github repository link which contains
downloadable pdf links.
* Remove broken links
Remove broken links and update available links from
web.archive.org.
* Update broken link with updated link.
Update the description for the updated link.
* Update broken links with links from web.archive.org
Remove dead links.
* Restore path to original link instead of web.archive.org
The link seems to be working fine. It was not loading
on my network, probably due to regional restrictions.
* Remove github link which is no longer maintained.
Github link consisted of list of Big Data resources.
The repository has been deleted by the user.
Hence deleting the entry.
* 1. Domain name http://reactjs.cn was sold and it is not related to react js for now. So I change it to another available site.
2. Tweak React to React.js
* fix ordering
Thanks for the contribution!
* add three book in free-programming-books-zh.md `Python` section
* order of adjustment
* remove the book in english and add author
@52fhy Thanks for being a contributor to F-P-B! Next time, remember to check the Travis CI output, it makes it much easier for the maintainers.
* Update PHP and Shell.
* update python and php
* update shell
* fix number of blank lines between sections
