readme: add initial version of model card

Hey,

this PR adds the initial version of model card.

README.md

@@ -80,5 +80,5 @@ is reported:
 
 The result in bold shows the performance of the current viewed model.
 
-Additionally, the Flair [training log](training.log) and [TensorBoard logs](tensorboard) are also uploaded to the model
+Additionally, the Flair [training log](training.log) and [TensorBoard logs](../../tensorboard) are also uploaded to the model
 hub.