[doc] add open-source contribution invitation (#2714)

* [doc] fix typo

* [doc] add invitation

README.md

@@ -3,7 +3,7 @@
 
    [![logo](https://raw.githubusercontent.com/hpcaitech/public_assets/main/colossalai/img/colossal-ai_logo_vertical.png)](https://www.colossalai.org/)
 
-   Colossal-AI: Make big AI models cheaper, easier, and scalable
+   Colossal-AI: Making big AI models cheaper, easier, and scalable
 
    <h3> <a href="https://arxiv.org/abs/2110.14883"> Paper </a> |
    <a href="https://www.colossalai.org/"> Documentation </a> |

applications/ChatGPT/README.md

@@ -60,6 +60,19 @@ We also support training reward model with true-world data. See `examples/train_
 - [ ] integrate with Ray
 - [ ] support more RL paradigms, like Implicit Language Q-Learning (ILQL)
 
+## Invitation to open-source contribution
+Referring to the successful attempts of [BLOOM](https://bigscience.huggingface.co/) and [Stable Diffusion](https://en.wikipedia.org/wiki/Stable_Diffusion), any and all developers and partners with computing powers, datasets, models are welcome to join and build an ecosystem with Colossal-AI, making efforts towards the era of big AI models from the starting point of replicating ChatGPT!
+
+You may contact us or participate in the following ways:
+1. Posting an [issue](https://github.com/hpcaitech/ColossalAI/issues/new/choose) or submitting a [PR](https://github.com/hpcaitech/ColossalAI/pulls) on GitHub
+2. Join the Colossal-AI community on 
+[Slack](https://join.slack.com/t/colossalaiworkspace/shared_invite/zt-z7b26eeb-CBp7jouvu~r0~lcFzX832w),
+and [WeChat](https://raw.githubusercontent.com/hpcaitech/public_assets/main/colossalai/img/WeChat.png "qrcode") to share your ideas.
+3. Check out and fill in the [cooperation proposal](https://www.hpc-ai.tech/partners)
+4. Send your proposal to email contact@hpcaitech.com
+
+Thanks so much to all of our amazing contributors!
+
 ## Quick Preview
 <p id="ChatGPT_scaling" align="center">
 <img src="https://raw.githubusercontent.com/hpcaitech/public_assets/main/applications/chatgpt/ChatGPT%20scaling.png" width=800/>