Update README.md

Author: ygongdev

README.md

@@ -1,17 +1,26 @@
 # slackoverflow
 A Slack bot for your stackoverflow needs.
 
-## Features
+# Table of Contents
+1. [Features](#features)
+2. [Integration](#integration)
+3. [Usage](#usage)
+4. [Development](#development)
+5. [Contributing](#contributing)
+6. [Contributors](#contributors)
+7. [License](#license)
+
+## Features <a name="features"></a>
   * Pulls the top answer of the most relevant question matching your query.
 
-## Integration
+## Integration <a name="integration"></a>
 Head over to http://adamhe.me/slack-bots/ and click on the `Add to Slack` button to add slackoverflow into your team!
 
-## Usage
+## Usage <a name="usage"></a>
   * Open Slack, either browser or desktop.
   * In any channel, mention the bot along with a question that you want to ask on stackoverflow, e.g `@slackoverflow how does a es6 promise work?` You can also direct message the bot directly if you don't want to clutter a channel.
 
-## Development
+## Development <a name="development"></a>
 1. Create an app on slack.
 2. Obtain your api token.
 3. Add your api token into your environment as `SLACK_API_TOKEN`. 
@@ -20,8 +29,11 @@ Head over to http://adamhe.me/slack-bots/ and click on the `Add to Slack` button
 6. Add the bot into any Slack teams (most likely one that you made for testing/developing).
 7. Run the bot via `python slackoverflow.py` and have fun developing!
 
-## Contributor Guide
-[CONTRIBUTING Guide](https://github.com/ygongdev/slackoverflow/blob/master/CONTRIBUTING.md)
+## Contributing <a name="contributing"></a>
+[Contributing Guide](https://github.com/ygongdev/slackoverflow/blob/master/CONTRIBUTING.md)
+
+## Contributors <a name="contributors"></a>
+[Contribuors](https://github.com/ygongdev/slackoverflow/blob/master/CONTRIBUTORS.md)
 
-## License 
+## License <a name="license"></a>
 [MIT License](https://github.com/ygongdev/slackoverflow/blob/master/LICENSE.md)