Fix reference to example (huggingface#184)

README.md

@@ -92,7 +92,7 @@ train_stats = ppo_trainer.step([query_tensor[0]], [response_tensor[0]], reward)
 ```
 
 ### Advanced example: IMDB sentiment
-For a detailed example check out the example python script `examples/scripts/ppo-sentiment.py`, where GPT2 is fine-tuned to generate positive movie reviews. An few examples from the language models before and after optimisation are given below:
+For a detailed example check out the example python script `examples/sentiment/scripts/gpt2-sentiment.py`, where GPT2 is fine-tuned to generate positive movie reviews. An few examples from the language models before and after optimisation are given below:
 
 <div style="text-align: center">
 <img src="https://huggingface.co/datasets/trl-internal-testing/example-images/resolve/main/images/table_imdb_preview.png" width="800">
@@ -118,4 +118,4 @@ The language models utilize the `transformers` library by 🤗 Hugging Face.
   journal = {GitHub repository},
   howpublished = {\url{https://github.com/lvwerra/trl}}
 }
-```
+```