Fixed missing import in code example.

README.md

@@ -47,7 +47,7 @@ This model can handle mismatched question-context pairs. Make sure to specify `h
 __Example usage:__
 
 ```python
->>> from transformers import AutoModelForQuestionAnswering, AutoTokenizer
+>>> from transformers import AutoModelForQuestionAnswering, AutoTokenizer, QuestionAnsweringPipeline
 >>> model = AutoModelForQuestionAnswering.from_pretrained("squirro/distilroberta-base-squad_v2")
 >>> tokenizer = AutoTokenizer.from_pretrained("squirro/distilroberta-base-squad_v2")
 >>> qa_model = QuestionAnsweringPipeline(model, tokenizer)