Add/Update Badges on README

Author: pushkyn

README.md

@@ -1,5 +1,10 @@
+![SendGrid Logo](https://uiux.s3.amazonaws.com/2016-logos/email-logo%402x.png)
+
 [![BuildStatus](https://travis-ci.org/sendgrid/sendgrid-csharp.png?branch=master)](https://travis-ci.org/sendgrid/sendgrid-csharp)
 [![Email Notifications Badge](https://dx.sendgrid.com/badge/csharp)](https://dx.sendgrid.com/newsletter/csharp)
+[![MIT licensed](https://img.shields.io/badge/license-MIT-blue.svg)](./LICENSE.txt)
+[![Twitter Follow](https://img.shields.io/twitter/follow/sendgrid.svg?style=social&label=Follow)](https://twitter.com/sendgrid)
+[![GitHub contributors](https://img.shields.io/github/contributors/sendgrid/sendgrid-csharp.svg)](https://github.com/sendgrid/sendgrid-csharp/graphs/contributors)
 
 <a name="announcements"></a>
 # Announcements
@@ -34,6 +39,7 @@ We appreciate your continued support, thank you!
 * [How to Contribute](#contribute)
 * [Troubleshooting](#troubleshooting)
 * [About](#about)
+* [License](#license)
 
 
 <a name="installation"></a>
@@ -255,4 +261,5 @@ sendgrid-csharp is guided and supported by the SendGrid [Developer Experience Te
 
 sendgrid-csharp is maintained and funded by SendGrid, Inc. The names and logos for sendgrid-csharp are trademarks of SendGrid, Inc.
 
-![SendGrid Logo](https://uiux.s3.amazonaws.com/2016-logos/email-logo%402x.png)
+# License
+[The MIT License (MIT)](LICENSE.txt)