* Sync zh and zh-hant versions.
* Remove the polyfill.io link from mkdocs.yml
* Update contributors' info for code reviewers and en/zh-hant versions reviewers.
* Fix graph.md
* Update avatars for English version reviewers.
* Sync zh and zh-hant versions.
* Add Ruby and Kotlin icons
Add the avatar of @curtishd
* Update README
* Synchronize zh-hant and zh versions.
* Translate the pythontutor blocks to traditional Chinese
* Fix en/mkdocs.yml
* Update the landing page of the en version.
* Fix the Dockerfile
* Refine the en landingpage
* Fix en landing page
* Reset the README.md
* Use Roboto mono as the font of the footers
* Bug fixes
* Add the introduction to the paper book.
* Add the 'new' label to the toc
* Turn off the autoplay
* Polish the intro to paperbook
* Update suggestions.md
* Add announcement of the paper book release
* Fix size of svg
* Update contrib rocks image
* Optimize HTML of the landing page
* Fix the line breaks