Remove Gitter from README
# K-9 Mail
[![Build Status](https://k9mail.ci.cloudbees.com/job/development%20(master)/badge/icon)](https://k9mail.ci.cloudbees.com/job/development%20(master)/)
[![Latest release](https://img.shields.io/github/release/k9mail/k-9.svg?style=flat-square)](https://github.com/k9mail/k-9/releases/latest)
-[![Join the chat](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/k9mail/k-9)
K-9 Mail is an open-source email client for Android.
@@ -56,7 +55,6 @@ Aside from discussing changes in [pull requests](https://github.com/k9mail/k-9/p
[issues](https://github.com/k9mail/k-9/issues) we use the following communication services:
- IRC chat, [#k-9 on the Freenode network](https://webchat.freenode.net/?channels=%23k-9)
-- [Gitter](https://gitter.im/k9mail/k-9)
- [Developer mailing list](https://groups.google.com/forum/#!forum/k-9-dev)
