message: Added Twitter badge
diff: <a href="https://spectrum.chat/wasmer">
  <img src="https://withspectrum.github.io/badge/badge.svg" alt="Join the Wasmer Community">
  </a>
  + <a href="https://twitter.com/wasmerio">
  + <img alt="Follow @wasmerio on Twitter" src="https://img.shields.io/twitter/follow/wasmerio?label=%40wasmerio&style=social">
  + </a>
  </p>
  ## Introduction
  