docs: Add repo overview diagram (#1403)

Signed-off-by: Wenwen Gao <[email protected]>
Signed-off-by: Terry Kong <[email protected]>
Co-authored-by: Terry Kong <[email protected]>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: 3 people

README.md

@@ -30,6 +30,8 @@
 
 **Nemo RL** is an open-source post-training library under the [NVIDIA NeMo Framework](https://github.com/NVIDIA-NeMo), designed to streamline and scale reinforcement learning methods for multimodal models (LLMs, VLMs etc.). Designed for flexibility, reproducibility, and scale, NeMo RL enables both small-scale experiments and massive multi-GPU, multi-node deployments for fast experimentation in research and production environments.
 
+![NeMo RL Architecture Diagram](https://raw.githubusercontent.com/NVIDIA-NeMo/RL/refs/heads/main/docs/assets/RL_diagram.png)
+
 What you can expect:
 - **Flexibility** with a modular design that allows easy integration and customization.
 - **Efficient resource management using Ray**, enabling scalable and flexible deployment across different hardware configurations.