[DOC]: 可以提供使用ColossalAI 训练自定义的模型

[lianNice]

📚 The doc issue

可以提供使用ColossalAI 训练自定义的模型，使用TP+PP训练方法的完整样例代码吗？ Policy怎么写呢？ 可以给个简单的例子吗？

[Issues-translate-bot]

Bot detected the issue body's language is not English, translate it automatically. 👯👭🏻🧑‍🤝‍🧑👫🧑🏿‍🤝‍🧑🏻👩🏾‍🤝‍👨🏿👬🏿

---

Title: [DOC]: Can provide custom models trained using ColossalAI

📚 The doc issue

Can you provide complete sample code for training customized models using ColossalAI and using TP+PP training methods? How to write Policy? Can you give a simple example?