add twitter account to start page (#159)

Author: olaoluwasalami

website/docs/Getting-Started.md

@@ -70,6 +70,7 @@ response = autogen.Completion.create(context=test_instance, **config)
 * Read [SDK](/docs/reference/agentchat/conversable_agent/).
 * Learn about [research](/docs/Research) around AutoGen.
 * Chat on [Discord](https://discord.gg/pAbnFJrkgZ).
+* Follow on [Twitter](https://twitter.com/pyautogen).
 
 If you like our project, please give it a [star](https://github.com/microsoft/autogen/stargazers) on GitHub. If you are interested in contributing, please read [Contributor's Guide](/docs/Contribute).