Update README

Author: keith

README.md

@@ -2,11 +2,34 @@
 
 A simple script for querying contacts from the command line.
 
-## [mutt](http://www.mutt.org/) integration
+Usage:
+
+```sh
+$ contacts query
+NAME	EMAIL
+[email protected]	First Last
+```
+
+## Installation
+
+```sh
+brew install keith/formulae/contacts-cli
+```
+
+### [mutt](http://www.mutt.org/) integration
 
 Somewhere in your `muttrc`:
 
 ```
 set query_command="contacts '%s'"
 bind editor <Tab> complete-query
 ```
+
+##### Notes
+
+- This is a simplified replacement for the unmaintained
+  [contacts](http://www.gnufoo.org/contacts/contacts.html)
+- This is distributed as a compiled executable rather than a swift
+  script to help with swift compatibility during new releases.
+- If you have trouble running the script inside tmux see [this
+  issue](https://github.com/ChrisJohnsen/tmux-MacOSX-pasteboard/issues/43)