add instruction

README.md

@@ -1,2 +1,47 @@
 Slack Invite Automation
 ------------
+
+A tiny web application to invite a user info your slack team.
+
+Inspired by
+[How I hacked Slack into a community platform with Typeform](https://levels.io/slack-typeform-auto-invite-sign-ups/)
+and
+[Socket.io's slack page](http://socket.io/slack/).
+
+## Setting
+fill out `config.js` as your infomation.
+
+* `community`: your cummunity or team name to display on join page.
+* `slackUrl` : your slack team url (ex: socketio.slack.com)
+* `slacktoken` : access token of slack.
+  You can generate it in <https://api.slack.com/web#auth>
+* `channels` : channels to join when the user is invited.(Array)
+  You can find id of channels in your slack.(look at sidebar on the left)
+
+  channel list's HTML looks like:
+
+    ```html
+    <li class="channel_C024R4462 channel ">
+      <a class="channel_name" data-channel-id="C024R4462">
+        <span class="unread_just_C024R4462 unread_just hidden">0</span>
+        <span class="unread_highlight_C024R4462 unread_highlight hidden">0</span>
+        <span class="overflow-ellipsis"><span class="prefix">#</span>codeport</span>
+      </a>
+    </li>
+    ```
+
+  the value of `data-channel-id` is channel id.(`C024R44` in above example)
+
+## Run
+[Node.js](http://nodejs.org/) is required.
+
+```shell
+$ git clone git@github.com:outsideris/slack-invite-automation.git
+$ cd slack-invite-automation
+$ npm install
+$ bin/www
+```
+
+You can access <http://localhost:3000> on your web browser.
+
+![](https://raw.github.com/outsideris/slack-invite-automation/master/screenshots/join-page.png)