Improve model card with metadata and details

This PR improves the model card by:

- Adding the `pipeline_tag: image-to-image` to clarify the model's function.
- Specifying the `library_name: diffusers` based on the model's use of diffusion models.
- Correcting the license to `cc-by-nc-sa-4.0`.
- Adding a more descriptive model description.

README.md

@@ -1,7 +1,18 @@
 ---
-license: cc-by-4.0
+license: cc-by-nc-sa-4.0
+library_name: diffusers
+pipeline_tag: image-to-image
 ---
+
+This model is a diffusion model trained to generate augmentations for cardiac ultrasound images, as described in [Generative augmentations for improved cardiac ultrasound segmentation using diffusion models](https://hf.co/papers/2502.20100).  These augmentations improve the robustness of segmentation models trained on cardiac ultrasound data.  The model is designed to increase the diversity of training data, leading to better generalization to unseen datasets.
+
 You should cite the following paper when using the code in this repository:
 
 Van De Vyver, Gilles, et al. "Generative augmentations for improved cardiac ultrasound segmentation using diffusion models." arXiv preprint arXiv:2502.20100 (2025).
-https://arxiv.org/abs/2502.20100
+https://arxiv.org/abs/2502.20100
+
+Blog post: [https://gillesvandevyver.com/#/projects/generative-ai](https://gillesvandevyver.com/#/projects/generative-ai)
+
+Code: https://github.com/GillesVanDeVyver/EchoGAINS
+
+A Jupyter notebook tutorial is available at [tutorial/tutorial.ipynb](tutorial/tutorial.ipynb).