add a documentation for editing the website

[tuxette]

and additionally, add a "fork me" link on the website

[njtierney]

This: #19

is an example of adding a paper to the website, this might help?

[njtierney]

Create a .github/ folder with a template for the issue and pull requests as a starting point.

See https://github.com/njtierney/naniar/tree/master/.github for a reference

[tuxette]

Answer on "for me" banner
The "for me" image from scikit-learn is available here:
https://github.com/scikit-learn/scikit-learn.github.io/blob/master/0.21/_static/img/forkme.png
is it open to re-use? If so, I will be able to put it easily on our website (code is:

<a href="https://github.com/scikit-learn/scikit-learn">
  <img class="fork-me"
       style="position: absolute; top: 0; right: 0; border: 0;"
       src="_static/img/forkme.png"
       alt="Fork me on GitHub" />
</a>

in headers).

[njtierney]

This site has some references on how to add a link in the corner: https://holtzy.github.io/Pimp-my-rmd/#github_link_in_corner

We could also add an editing link, as describe here:

yihui/hugo-xmin#6

Which can be seen here:

https://yihui.name/en/2019/07/romain-lesur/

[tuxette]

corner done in commit #ccde2f9d6f764ec6e39be7f9cc1b136978e6ea78 and credited in commit #aac587333b33a345ff8e45fe60b5334c206a9f8d