Add default chat template to tokenizer_config.json

tokenizer_config.json

@@ -29,5 +29,6 @@
     "normalized": true,
     "rstrip": false,
     "single_word": false
-  }
-}
+  },
+  "chat_template": "{% for message in messages %}{{ message.content }}{{ eos_token }}{% endfor %}"
+}