Add tokenizer

Add the tokenizer trained on the BookCorpusOpen dataset.

special_tokens_map.json

@@ -0,0 +1,3 @@
+{
+  "eos_token": "<|endoftext|>"
+}

tokenizer_config.json

@@ -0,0 +1,16 @@
+{
+  "added_tokens_decoder": {
+    "0": {
+      "content": "<|endoftext|>",
+      "lstrip": false,
+      "normalized": false,
+      "rstrip": false,
+      "single_word": false,
+      "special": true
+    }
+  },
+  "clean_up_tokenization_spaces": true,
+  "eos_token": "<|endoftext|>",
+  "model_max_length": 1000000000000000019884624838656,
+  "tokenizer_class": "PreTrainedTokenizerFast"
+}