Add model card with metadata and link to code

This PR adds a model card to the repository, linking it to the paper [LLM-Supported Natural Language to Bash Translation](https://arxiv.org/abs/2502.06858).

README.md

@@ -1 +1,9 @@
-https://arxiv.org/abs/2502.06858
+---
+library_name: transformers
+pipeline_tag: text-generation
+license: apache-2.0
+---
+
+The model was presented in the paper [LLM-Supported Natural Language to Bash Translation](https://arxiv.org/abs/2502.06858).
+
+Code: https://github.com/westenfelder/NL2SH