添加【数学】Free online math resources for Machine Learning

Author: amusi

docs/数学.md

@@ -114,4 +114,5 @@
 - [机器学习理论篇1：机器学习的数学基础](https://zhuanlan.zhihu.com/p/25197792)
 - [图像处理中的数学方法](http://bicmr.pku.edu.cn/~dongbin/Teaching_files/%E5%9B%BE%E5%83%8F%E5%A4%84%E7%90%86%E4%B8%AD%E7%9A%84%E6%95%B0%E5%AD%A6%E6%96%B9%E6%B3%95-18-19/index.html)
 - [MIT数学课程](https://ocw.mit.edu/courses/mathematics/)
-- [优秀的程序员需要懂那些数学知识？](https://www.zhihu.com/question/21425201/answer/632269759)
+- [优秀的程序员需要懂那些数学知识？](https://www.zhihu.com/question/21425201/answer/632269759)
+- [Free online math resources for Machine Learning](https://github.com/Machine-Learning-Tokyo/Math_resources)