Migrate model card from transformers-repo

Read announcement at https://discuss.huggingface.co/t/announcement-all-model-cards-will-be-migrated-to-hf-co-model-repos/2755
Original file history: https://github.com/huggingface/transformers/commits/master/model_cards/google/mobilebert-uncased/README.md

README.md

@@ -0,0 +1,32 @@
+---
+language: en
+thumbnail: https://huggingface.co/front/thumbnails/google.png
+
+license: apache-2.0
+---
+
+## MobileBERT: a Compact Task-Agnostic BERT for Resource-Limited Devices
+
+MobileBERT is a thin version of BERT_LARGE, while equipped with bottleneck structures and a carefully designed balance
+between self-attentions and feed-forward networks.
+
+This checkpoint is the original MobileBert Optimized Uncased English: 
+[uncased_L-24_H-128_B-512_A-4_F-4_OPT](https://storage.googleapis.com/cloud-tpu-checkpoints/mobilebert/uncased_L-24_H-128_B-512_A-4_F-4_OPT.tar.gz) 
+checkpoint.
+
+## How to use MobileBERT in `transformers`
+
+```python
+from transformers import pipeline
+
+fill_mask = pipeline(
+	"fill-mask",
+	model="google/mobilebert-uncased",
+	tokenizer="google/mobilebert-uncased"
+)
+
+print(
+	fill_mask(f"HuggingFace is creating a {fill_mask.tokenizer.mask_token} that the community uses to solve NLP tasks.")
+)
+
+```