community: add link to slace workspace (#511)

We created a slack workspace for flashinfer discussions.

README.md

@@ -9,7 +9,7 @@ Kernel Library for LLM Serving
 </h1>
 
 <p align="center">
-| <a href="https://flashinfer.ai"><b>Blog</b></a> | <a href="https://docs.flashinfer.ai"><b>Documentation</b></a> | <a href="https://github.com/orgs/flashinfer-ai/discussions"><b>Discussion Forum</b></a> |
+| <a href="https://flashinfer.ai"><b>Blog</b></a> | <a href="https://docs.flashinfer.ai"><b>Documentation</b></a> | <a href="https://join.slack.com/t/flashinfer/shared_invite/zt-2r93kj2aq-wZnC2n_Z2~mf73N5qnVGGA"><b>Slack</b></a>|  <a href="https://github.com/orgs/flashinfer-ai/discussions"><b>Discussion Forum</b></a> |
 </p>
 
 [![Release](https://github.com/flashinfer-ai/flashinfer/actions/workflows/release_wheel.yml/badge.svg)](https://github.com/flashinfer-ai/flashinfer/actions/workflows/release_wheel.yml)
@@ -26,6 +26,7 @@ The unique features of FlashInfer include:
 FlashInfer support PyTorch, TVM and C++ (header-only) APIs, and can be easily integrated into existing projects.
 
 ## News
+- [Sept 2024] We've launched a [Slack](https://join.slack.com/t/flashinfer/shared_invite/zt-2r93kj2aq-wZnC2n_Z2~mf73N5qnVGGA) workspace for Flashinfer users and developers. Join us for timely support, discussions, updates and knowledge sharing!
 - [Jan 31, 2024] [Blog Post](https://flashinfer.ai/2024/01/08/cascade-inference.html) Cascade Inference: Memory-Efficient Shared Prefix Batch Decoding
 - [Jan 31, 2024] [Blog Post](https://flashinfer.ai/2024/01/03/introduce-flashinfer.html) Accelerating Self-Attentions for LLM Serving with FlashInfer