update doc

README.cn.md

@@ -321,6 +321,8 @@ eval "$(lua /path/to/z.lua --init bash enhanced once echo fzf)"
 
 有了 fzf 的帮助，bash 下补全也非常方便了。注意看左边的权重，fzf 搜索过滤的顺序是有讲究的，Frecent 权重越高的越靠前，不是乱排序的，更不是简单的按字符串字母排序。这里完全保证权重越高的路径越靠前。
 
+`z.lua` 可以同 [fz](https://github.com/changyuheng/fz) 协作以提供**更好的补全结果**，详细见 [FAQ](https://github.com/skywind3000/z.lua/wiki/FAQ#fzsh-for-better-completion)。
+
 注意：该功能在初始化 z.lua 之前，会检测 $PATH 中是否有 fzf 这个程序，有的话才启用。
 
 

README.md

@@ -341,6 +341,8 @@ Then press `<tab>` after `z xxx`:
 
 With the help of fzf, completion in bash is much easier now. 
 
+`z.lua` can cooperate with [fz](https://github.com/changyuheng/fz) for **better completion** result in both bash and zsh, for more information see [FAQ](https://github.com/skywind3000/z.lua/wiki/FAQ#fzsh-for-better-completion).
+
 NOTE: To enable this, command `fzf` must be found in `$PATH` before initialization.
 
 
@@ -454,6 +456,7 @@ As you see, z.lua is the fastest one and requires less resource.
 
 ## History
 
+- 1.5.4 (2019-02-19): fixed: file/path existence detection fails on read-only fs (closed [#49](https://github.com/skywind3000/z.lua/issues/49) by [@contrun](https://github.com/contrun)).
 - 1.5.3 (2019-02-17): new `$_ZL_FZF_FLAG` for passing additional flags to fzf, add `-e` argument to fzf.
 - 1.5.2 (2019-02-16): be aware of all arguments in fzf completion.
 - 1.5.1 (2019-02-15): new: simulated dir stack by `z -`, `z --` and `z -{num}`.