Add 6本值得推荐的MySQL学习书籍

Author: YSGStudyHards

README.md

@@ -451,6 +451,7 @@
 * [MySQL基础快速入门](https://mp.weixin.qq.com/s/pnbI7xSDk7_hQMLgVryPaA)
 * [MySQL基础知识汇总](http://www.cyc2018.xyz/%E6%95%B0%E6%8D%AE%E5%BA%93/MySQL.html#%E4%B8%80%E3%80%81%E7%B4%A2%E5%BC%95)
 * [21分钟MySQL入门教程](http://www.cnblogs.com/mr-wid/archive/2013/05/09/3068229.html)
+* [6本值得推荐的MySQL学习书籍](https://mp.weixin.qq.com/s/bPAKZsXwDxRy5mzEODFljw)
 * [MySQL中，21个写SQL的好习惯](https://mp.weixin.qq.com/s/pN6azE6v4y9sk96FJqctBw)
 * [MySQL夺命16问，你能回答出几个？](https://mp.weixin.qq.com/s/eJepG60ll0gaEPVb1IAKVA)
 * [MySQL入门教程（MySQL tutorial book）](https://github.com/jaywcjlove/mysql-tutorial)