improve readme with classes information

README.md

@@ -9,6 +9,14 @@ This model card aims to simplify the use of the [portuguese Bert, a.k.a, Bertimb
 
 For this model card the we used the <mark style="background-color: #d3d3d3"> **BERT-CRF (selective scenario, 5 classes)** </mark> model available in the [ner_evaluation](https://github.com/neuralmind-ai/portuguese-bert/tree/master/ner_evaluation) folder of the original Bertimbau repo.
 
+Available classes are:
+
++ PESSOA
++ ORGANIZACAO
++ LOCAL
++ TEMPO
++ VALOR
+
 ## Usage
 
 ```