Added model cards for Romanian BERT models (#4437)

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Co-authored-by: Julien Chaumond <chaumond@gmail.com>

model_cards/dumitrescustefan/bert-base-romanian-cased-v1/README.md

+---
+language: romanian
+---
+
+# bert-base-romanian-cased-v1
+
+The BERT **base**, **cased** model for Romanian, trained on a 15GB corpus, version ![v1.0](https://img.shields.io/badge/v1.0-21%20Apr%202020-ff6666)
+
+### How to use
+
+```python
+from transformers import AutoTokenizer, AutoModel
+import torch
+# load tokenizer and model
+tokenizer = AutoTokenizer.from_pretrained("dumitrescustefan/bert-base-romanian-cased-v1")
+model = AutoModel.from_pretrained("dumitrescustefan/bert-base-romanian-cased-v1")
+# tokenize a sentence and run through the model
+input_ids = torch.tensor(tokenizer.encode("Acesta este un test.", add_special_tokens=True)).unsqueeze(0)  # Batch size 1
+outputs = model(input_ids)
+# get encoding
+last_hidden_states = outputs[0]  # The last hidden-state is the first element of the output tuple
+```
+
+### Evaluation
+
+Evaluation is performed on Universal Dependencies [Romanian RRT](https://universaldependencies.org/treebanks/ro_rrt/index.html) UPOS, XPOS and LAS, and on a NER task based on [RONEC](https://github.com/dumitrescustefan/ronec). Details, as well as more in-depth tests not shown here, are given in the dedicated [evaluation page](https://github.com/dumitrescustefan/Romanian-Transformers/tree/master/evaluation/README.md). 
+
+The baseline is the [Multilingual BERT](https://github.com/google-research/bert/blob/master/multilingual.md) model ``bert-base-multilingual-(un)cased``, as at the time of writing it was the only available BERT model that works on Romanian.
+
+| Model                          |  UPOS |  XPOS  |  NER  |  LAS  |
+|--------------------------------|:-----:|:------:|:-----:|:-----:|
+| bert-base-multilingual-cased   | 97.87 |  96.16 | 84.13 | 88.04 |
+| bert-base-romanian-cased-v1    | **98.00** |  **96.46** | **85.88** | **89.69** |
+
+### Corpus 
+
+The model is trained on the following corpora (stats in the table below are after cleaning):
+
+| Corpus    	| Lines(M) 	| Words(M) 	| Chars(B) 	| Size(GB) 	|
+|-----------	|:--------:	|:--------:	|:--------:	|:--------:	|
+| OPUS      	|   55.05  	|  635.04  	|   4.045  	|    3.8   	|
+| OSCAR     	|   33.56  	|  1725.82 	|  11.411  	|    11    	|
+| Wikipedia 	|   1.54   	|   60.47  	|   0.411  	|    0.4   	|
+| **Total**     	|   **90.15**  	|  **2421.33** 	|  **15.867**  	|   **15.2**   	|
+
+#### Acknowledgements
+
+- We'd like to thank [Sampo Pyysalo](https://github.com/spyysalo) from TurkuNLP for helping us out with the compute needed to pretrain the v1.0 BERT models. He's awesome!

model_cards/dumitrescustefan/bert-base-romanian-uncased-v1/README.md

+---
+language: romanian
+---
+
+# bert-base-romanian-uncased-v1
+
+The BERT **base**, **uncased** model for Romanian, trained on a 15GB corpus, version ![v1.0](https://img.shields.io/badge/v1.0-21%20Apr%202020-ff6666)
+
+### How to use
+
+```python
+from transformers import AutoTokenizer, AutoModel
+import torch
+
+# load tokenizer and model
+tokenizer = AutoTokenizer.from_pretrained("dumitrescustefan/bert-base-romanian-uncased-v1", do_lower_case=True)
+model = AutoModel.from_pretrained("dumitrescustefan/bert-base-romanian-uncased-v1")
+
+# tokenize a sentence and run through the model
+input_ids = torch.tensor(tokenizer.encode("Acesta este un test.", add_special_tokens=True)).unsqueeze(0)  # Batch size 1
+outputs = model(input_ids)
+
+# get encoding
+last_hidden_states = outputs[0]  # The last hidden-state is the first element of the output tuple
+```
+
+### Evaluation
+
+Evaluation is performed on Universal Dependencies [Romanian RRT](https://universaldependencies.org/treebanks/ro_rrt/index.html) UPOS, XPOS and LAS, and on a NER task based on [RONEC](https://github.com/dumitrescustefan/ronec). Details, as well as more in-depth tests not shown here, are given in the dedicated [evaluation page](https://github.com/dumitrescustefan/Romanian-Transformers/tree/master/evaluation/README.md). 
+
+The baseline is the [Multilingual BERT](https://github.com/google-research/bert/blob/master/multilingual.md) model ``bert-base-multilingual-(un)cased``, as at the time of writing it was the only available BERT model that works on Romanian.
+
+| Model                          |  UPOS |  XPOS  |  NER  |  LAS  |
+|--------------------------------|:-----:|:------:|:-----:|:-----:|
+| bert-base-multilingual-uncased | 97.65 |  95.72 | 83.91 | 87.65 |
+| bert-base-romanian-uncased-v1  | **98.18** |  **96.84** | **85.26** | **89.61** |
+
+### Corpus 
+
+The model is trained on the following corpora (stats in the table below are after cleaning):
+
+| Corpus    	| Lines(M) 	| Words(M) 	| Chars(B) 	| Size(GB) 	|
+|-----------	|:--------:	|:--------:	|:--------:	|:--------:	|
+| OPUS      	|   55.05  	|  635.04  	|   4.045  	|    3.8   	|
+| OSCAR     	|   33.56  	|  1725.82 	|  11.411  	|    11    	|
+| Wikipedia 	|   1.54   	|   60.47  	|   0.411  	|    0.4   	|
+| **Total**     	|   **90.15**  	|  **2421.33** 	|  **15.867**  	|   **15.2**   	|
+
+#### Acknowledgements
+
+- We'd like to thank [Sampo Pyysalo](https://github.com/spyysalo) from TurkuNLP for helping us out with the compute needed to pretrain the v1.0 BERT models. He's awesome!