MathJax is a library to render TeX or MathML mathematical expressions.
When doing mathematics MOOC, I've discovered this is a perfect tool to gather on the English Wikipedia mathematical notations of formula I want to write, see them visually in the screen, and get the code with a contextual menu offered by MathJax.
This plugin allows to enable MathJax on Discourse.
$ ssh dwellers docker exec -it app bash $ cd /var/www/discourse $ bundle exec rake plugin:install repo=https://github.com/kasperpeulen/discourse-mathjax [...] $ bundle exec rake assets:precompile URGENT: FATAL: Peer authentication failed for user "discourse" Failed to initialize site default Purging temp files Bundling assets [...] Tasks: TOP => assets:precompile (See full trace by running task with --trace)
Peer authentication failed for user "discourse" let me think this should have been done as the discourse user.
$ chown -R discourse /var/www/discourse/ $ kill -9 [unicorn pids (including unicorn_launcher but NOT runsv unicorn]
Unicorn restarted itself, with the forum updated and plugin loaded.
Plug-in must then be enabled in admin settings (in the MathJax tab, not the plugins tab).