Update tokenizer.json

tokenizer.json

@@ -51,7 +51,7 @@
   "model": {
     "type": "BPE",
     "dropout": null,
-    "unk_token": null,
+    "unk_token": true,
     "continuing_subword_prefix": null,
     "end_of_word_suffix": null,
     "fuse_unk": false,
@@ -59,11 +59,16 @@
     "vocab": {
       "<|endoftext|>": 0,
       "<|padding|>": 1,
+      "<|padding|>": 8,
       "a": 2,
       "c": 3,
       "g": 4,
       "t": 5,
-      "n": 6
+      "n": 6, 
+      "y":7, 
+      "w":9, 
+      "k":10, 
+      "r":11
     },
     "merges": []
   }