Add reference to same model with model card

@Ezi



@Meg



@Julien-C

README.md

@@ -2,3 +2,5 @@
 language: de
 license: mit
 ---
+
+This model is the same as [dbmdz/bert-base-german-cased](https://huggingface.co/dbmdz/bert-base-german-cased). See the [dbmdz/bert-base-german-cased model card](https://huggingface.co/dbmdz/bert-base-german-cased) for details on the model.