Add default chat template to tokenizer_config.json

tokenizer_config.json

@@ -5,5 +5,6 @@
   "eos_token": "<|endoftext|>",
   "model_max_length": 2048,
   "tokenizer_class": "GPTNeoXTokenizer",
-  "unk_token": "<|endoftext|>"
-}
+  "unk_token": "<|endoftext|>",
+  "chat_template": "{% for message in messages %}{{ message.content }}{{ eos_token }}{% endfor %}"
+}