Add Portkey to readme

Author: vrushankportkey

README.md

@@ -23,6 +23,8 @@ Prompt engineering is kind of like alchemy. There's no clear way to predict what
 
 - **[Weights & Biases](https://wandb.ai/site/prompts) Logging**: Optional logging to [Weights & Biases](https://wandb.ai/site) of your configs such as temperature and max tokens, the system and user prompts for each part, the test cases used and the final ranked ELO rating for each candidate prompt. Set `use_wandb` to `True` to use. 
 
+- **[Portkey](https://portkey.ai)**: Optional tool to log and trace all the prompt chains and their responses. Set `use_portkey` to `True` to use.
+
 ## Setup
 1. [Open the notebook in Google Colab](https://colab.research.google.com/github/mshumer/gpt-prompt-engineer/blob/main/gpt_prompt_engineer.ipynb) or in a local Jupyter notebook. For classification, use [this one.](https://colab.research.google.com/drive/16NLMjqyuUWxcokE_NF6RwHD8grwEeoaJ?usp=sharing)