Add zsh's vcs_info to README

README.md

@@ -67,7 +67,9 @@ The symbols (or "markers") can be changed by editing the `prompt.sh` file direct
 
 - The [prompt now distributed with git](https://github.com/git/git/blob/master/contrib/completion/git-prompt.sh) offers a `GIT_PS1_SHOWUPSTREAM` option.
 
-- [Oh-my-zsh](https://github.com/robbyrussell/oh-my-zsh) also has its own [git-prompt](https://github.com/robbyrussell/oh-my-zsh/blob/master/plugins/gitfast/git-prompt.sh).  (It has 500 lines compared to our 200.)
+- Zsh now ships with [vcs_info](https://git-scm.com/book/tr/v2/Appendix-A%3A-Git-in-Other-Environments-Git-in-Zsh) which works for a variety of version control systems.  (Unfortunately the docs for this are a big gnarly.)
+
+- [Oh-my-zsh](https://github.com/robbyrussell/oh-my-zsh) has its own [git-prompt](https://github.com/robbyrussell/oh-my-zsh/blob/master/plugins/gitfast/git-prompt.sh).  (It has 500 lines compared to our 200.)
 
 - Inspiration for this fork came from [git-branch-status](https://gist.github.com/jehiah/1288596) by jehiah (a command, not a prompt)