add cn readme.

Author: yulongheli

README.zh-cn.md

@@ -0,0 +1,22 @@
+# Patch.js 采用的 Diff 算法
+
+## 安装
+
+```bash
+npm install patchjs-diff --save-dev
+```
+
+## API
+
+calcDiffData (src, dest)
+
+## 算法资料参考
+
+http://wiki.c2.com/?DiffAlgorithm
+
+https://github.com/mtjs/mt
+
+https://neil.fraser.name/software/diff_match_patch/myers.pdf
+
+https://code.google.com/p/google-diff-match-patch/
+