[chat]fix readme (#3429)

* fix stage 2

fix stage 2

* add torch

applications/Chat/examples/README.md

@@ -57,7 +57,7 @@ You can run the `examples/train_rm.sh` to start a reward model training.
 
 You can also use the following cmd to start training a reward model.
 ```
-torchrun --standalone --nproc_per_node=4 train_reward_model.py
+torchrun --standalone --nproc_per_node=4 train_reward_model.py \
     --pretrain "/path/to/LLaMa-7B/" \
     --model 'llama' \
     --strategy colossalai_zero2 \

applications/Chat/inference/README.md

@@ -51,6 +51,7 @@ Please ensure you have downloaded HF-format model weights of LLaMA models.
 Usage:
 
 ```python
+import torch
 from transformers import LlamaForCausalLM
 
 USE_8BIT = True # use 8-bit quantization; otherwise, use fp16