Add missing `model_type` to `config.json`

config.json

@@ -7,5 +7,6 @@
   "n_kv_heads": 8,
   "norm_eps": 1e-05,
   "vocab_size": 32000,
-  "sliding_window": 4096
+  "sliding_window": 4096,
+  "model_type": "mistral"
 }