Add Slack link (#131)

* add slack link

* fix

README.md

@@ -3,6 +3,7 @@
 [![Crates.io](https://img.shields.io/crates/v/vibrato)](https://crates.io/crates/vibrato)
 [![Documentation](https://docs.rs/vibrato/badge.svg)](https://docs.rs/vibrato)
 ![Build Status](https://github.com/daac-tools/vibrato/actions/workflows/rust.yml/badge.svg)
+[![Slack](https://img.shields.io/badge/join-chat-brightgreen?logo=slack)](https://join.slack.com/t/daac-tools/shared_invite/zt-1pwwqbcz4-KxL95Nam9VinpPlzUpEGyA)
 
 Vibrato is a fast implementation of tokenization (or morphological analysis) based on the Viterbi algorithm.
 
@@ -186,6 +187,13 @@ EOS
 
 The directory [docs](./docs/) provides descriptions of more advanced usages such as training or benchmarking.
 
+## Slack
+
+We have a Slack workspace for developers and users to ask questions and discuss a variety of topics.
+
+ * https://daac-tools.slack.com/
+ * Please get an invitation from [here](https://join.slack.com/t/daac-tools/shared_invite/zt-1pwwqbcz4-KxL95Nam9VinpPlzUpEGyA).
+
 ## License
 
 Licensed under either of