Add pipeline tag and update paper link/title

This PR improves the model card by:

* Adding the `pipeline_tag: text-to-image` so the model can be discovered at https://huggingface.co/models?pipeline_tag=text-to-image.
* Updating the model's description to accurately refer to the paper [AlignGuard: Scalable Safety Alignment for Text-to-Image Generation](https://huggingface.co/papers/2412.10493).
* Aligning the display names of the project page and GitHub repository links with the paper's title.

README.md

@@ -1,16 +1,18 @@
 ---
 library_name: diffusers
 license: mit
+pipeline_tag: text-to-image
 ---
-This is the official released checkpoint of **an aligned SD v2.1** of SafetyDPO: Scalable Safety Alignment for Text-to-Image Generation, designed to generate more safe images from our Safe-SD2.1. 
 
-Our project page is [🏠SafetyDPO HomePage](https://safetydpo.github.io/) and the GitHub repo is [⚙️SafetyDPO GitHub](https://github.com/Visualignment/SafetyDPO) where we released all the code and the data. 
+This is the official released checkpoint of **an aligned SD v2.1** for **AlignGuard: Scalable Safety Alignment for Text-to-Image Generation** ([paper](https://huggingface.co/papers/2412.10493)), designed to generate more safe images.
 
-In the future, we will release additional safe models. 
+Our project page is [🏠AlignGuard HomePage](https://safetydpo.github.io/) and the GitHub repo is [⚙️AlignGuard GitHub](https://github.com/Visualignment/SafetyDPO) where we released all the code and the data.
+
+In the future, we will release additional safe models.
 
 # Usage
 A simple use case of our model is:
-```
+```python
 from diffusers import DiffusionPipeline
 
 pipe = DiffusionPipeline.from_pretrained("Visualignment/safe-stable-diffusion-v2-1")