Card: link to collection, remove empty stubs

README.md

@@ -12,6 +12,8 @@ tags:
 
 # Model Card for diffusion
 
+Part of the [SO-101 block-to-bin collection](https://huggingface.co/collections/lichtphyz/so-101-block-to-bin-act-vs-diffusion-policy-6ad6ca5c5e111b426bb1f8a6) (models, training data and real-robot evaluations).
+
 <!-- Provide a quick summary of what the model is/does. -->
 
 
@@ -160,4 +162,4 @@ If you use this policy, please cite the method linked in the description above,
     howpublished = "\url{https://github.com/huggingface/lerobot}",
     year = {2024}
 }
-```
+```