adding gpt2

pytorch_pretrained_bert/__init__.py

@@ -13,6 +13,9 @@ from .modeling_openai import (OpenAIGPTConfig, OpenAIGPTModel,
                               load_tf_weights_in_openai_gpt)
 from .modeling_transfo_xl import (TransfoXLConfig, TransfoXLModel, TransfoXLLMHeadModel,
                                   load_tf_weights_in_transfo_xl)
+from .modeling_gpt2 import (GPT2Config, GPT2Model,
+                            GPT2LMHeadModel, GPT2DoubleHeadsModel,
+                            load_tf_weights_in_gpt2)
 
 from .optimization import BertAdam
 from .optimization_openai import OpenAIAdam