add chat template

tokenizer_config.json

@@ -158,7 +158,8 @@
     "<empty_output>"
   ],
   "bos_token": "<|endoftext|>",
-  "clean_up_tokenization_spaces": true,
+  "chat_template": "{% for message in messages %}{{'<|im_start|>' + message['role'] + '\n' + message['content'] + '<|im_end|>' + '\n'}}{% endfor %}{% if add_generation_prompt %}{{ '<|im_start|>assistant\n' }}{% endif %}",
+  "clean_up_tokenization_spaces": false,
   "eos_token": "<|endoftext|>",
   "model_max_length": 1000000000000000019884624838656,
   "tokenizer_class": "GPT2Tokenizer",