[Dataset requests] New datasets for Text Classification
Hi @jxmorris12 for now I think our `dl_manager` does not download from Kaggle.
@thomwolf , @lhoestq
We are missing a few datasets for Text Classification which is an important field.

Namely, it would be really nice to add:
- TREC-6 dataset (see here for instance: https://pytorchnlp.readthedocs.io/en/latest/source/torchnlp.datasets.html#torchnlp.datasets.trec_dataset)  **[done]**
- Yelp-5
- Movie review (Movie Review (MR) dataset [156]) **[done (same as rotten_tomatoes)]**
- SST (Stanford Sentiment Treebank) **[include in glue]**
- Multi-Perspective Question Answering (MPQA) dataset **[require authentication (indeed manual download)]**
- Amazon. This is a popular corpus of product reviews collected from the Amazon website [159]. It contains labels for both binary classification and multi-class (5-class) classification
- 20 Newsgroups. The 20 Newsgroups dataset  **[done]**
- Sogou News dataset **[done]**
- Reuters news. The Reuters-21578 dataset [165] **[done]**
- DBpedia. The DBpedia dataset [170]
- Ohsumed. The Ohsumed collection [171] is a subset of the MEDLINE database
- EUR-Lex. The EUR-Lex dataset
- WOS. The Web Of Science (WOS) dataset **[done]**
- PubMed. PubMed [173]
- TREC-QA. TREC-QA
- Quora. The Quora dataset [180]

All these datasets are cited in https://arxiv.org/abs/2004.03705
[Dataset requests] New datasets for Text Classification 
 We are missing a few datasets for Text Classification which is an important field.

Namely, it would be really nice to add:
- TREC-6 dataset (see here for instance: https://pytorchnlp.readthedocs.io/en/latest/source/torchnlp.datasets.html#torchnlp.datasets.trec_dataset)  **[done]**
- Yelp-5
- Movie review (Movie Review (MR) dataset [156]) **[done (same as rotten_tomatoes)]**
- SST (Stanford Sentiment Treebank) **[include in glue]**
- Multi-Perspective Question Answering (MPQA) dataset **[require authentication (indeed manual download)]**
- Amazon. This is a popular corpus of product reviews collected from the Amazon website [159]. It contains labels for both binary classification and multi-class (5-class) classification
- 20 Newsgroups. The 20 Newsgroups dataset  **[done]**
- Sogou News dataset **[done]**
- Reuters news. The Reuters-21578 dataset [165] **[done]**
- DBpedia. The DBpedia dataset [170]
- Ohsumed. The Ohsumed collection [171] is a subset of the MEDLINE database
- EUR-Lex. The EUR-Lex dataset
- WOS. The Web Of Science (WOS) dataset **[done]**
- PubMed. PubMed [173]
- TREC-QA. TREC-QA
- Quora. The Quora dataset [180]

All these datasets are cited in https://arxiv.org/abs/2004.03705 
 Hi @jxmorris12 for now I think our `dl_manager` does not download from Kaggle.
@thomwolf , @lhoestq