Versioning in documentation
Several versions of the documentation can now be accessed:

`huggingface.co/transformers` for the master release
`huggingface.co/transformers/v2.1.1` for the 2.1.1 official release and so on.
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/1604?src=pr&el=h1) Report
> Merging [#1604](https://codecov.io/gh/huggingface/transformers/pull/1604?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/ef1b8b2ae5ad1057154a126879f7eb8de685f862?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/1604/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/transformers/pull/1604?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #1604      +/-   ##
==========================================
- Coverage   86.17%   86.16%   -0.01%     
==========================================
  Files          91       91              
  Lines       13595    13593       -2     
==========================================
- Hits        11715    11713       -2     
  Misses       1880     1880
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/1604?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [transformers/tokenization\_ctrl.py](https://codecov.io/gh/huggingface/transformers/pull/1604/diff?src=pr&el=tree#diff-dHJhbnNmb3JtZXJzL3Rva2VuaXphdGlvbl9jdHJsLnB5) | `96.03% <0%> (-0.08%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/1604?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/1604?src=pr&el=footer). Last update [ef1b8b2...6e85bcc](https://codecov.io/gh/huggingface/transformers/pull/1604?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
<|||||>Ready to merge<|||||>Awesome!