add doc

README.md

@@ -1,6 +1,9 @@
 # slack-cli
 Simple command-line client for slack by golang
 
+![](https://img.shields.io/badge/golang-1.5.1-blue.svg?style=flat)
+[![GoDoc](https://godoc.org/github.com/takecy/slack-cli?status.svg)](https://godoc.org/github.com/takecy/slack-cli)
+
 ## Features
 * Post message only
 * Use Incoming Web hook service on slack

doc.go

@@ -0,0 +1,13 @@
+/*
+slack-cli is simple command-line client for slack.
+
+    $ go get github.com/takecy/slack-cli
+
+First is
+    $ slack-cli config <incoming web hook url>
+Post message
+  $ slack-cli post <message>
+Post to specific channel
+  $ slack-cli post -c general <message>
+*/
+package main