update Slack link

Author: zsdonghao

README.md

@@ -202,7 +202,7 @@ Examples can be found [in this repository](https://github.com/zsdonghao/tensorla
 
 ## Notes
 * TensorLayer provides two set of Convolutional layer APIs, see [(Professional)](http://tensorlayer.readthedocs.io/en/latest/modules/layers.html#convolutional-layer-pro) and [(Simplified)](http://tensorlayer.readthedocs.io/en/latest/modules/layers.html#convolutional-layer-simplified) on readthedocs website.
-* If you get into trouble, you can start a discussion on [Slack](https://join.slack.com/t/tensorlayer/shared_invite/MjExMjMzODAwNjI0LTE0OTk4ODEzMjUtNmVjNjQ4ZjMzMw), [Gitter](https://gitter.im/tensorlayer/Lobby#?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge>),
+* If you get into trouble, you can start a discussion on [Slack](https://join.slack.com/t/tensorlayer/shared_invite/MjI1NjQ5NTUxOTY5LTE1MDI3MDYwNTItYzYwNmFiZmZkOA), [Gitter](https://gitter.im/tensorlayer/Lobby#?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge>),
 [Help Wanted Issues](https://waffle.io/zsdonghao/tensorlayer),
 [QQ group](https://github.com/zsdonghao/tensorlayer/blob/master/img/img_qq.png) and [Wechat group](https://github.com/shorxp/tensorlayer-chinese/blob/master/docs/wechat_group.md).