2021 November 2
Made a backup AMI:
Scanalyst Backup 2021-11-02 ami-03331fe51ec62d4c2
/ snap-072d19f4ae0d3caa2
/server snap-071181bf8049f01ed
Made a mirror backup to Juno.
To install, remove, or modify a plug-in, according to:
https://meta.discourse.org/t/install-plugins-in-discourse/19157
edit the ~/discourse/image/containers/app.yml file and modify
the lines after:
- git clone https://github.com/discourse/docker_manager.git
which clone the Git repositories of the plug-ins. Then
rebuild the application with:
super
cd ~/discourse/image
./launcher rebuild app
The problem with MathJax was that I had installed the plug-in
to which I was directed by a Web search, that being:
https://github.com/kasperpeulen/discourse-mathjax
which I believe is actually linked to in several documents
on the Discourse site. This is, in fact, an old version of the
plug-in which is no longer compatible with Discourse and
causes the errors we were encountering. I finally found this
document:
https://meta.discourse.org/t/discourse-math-plugin/65770
which says that one should now use the "Official MathJax
Support for Discourse", which is hosted at:
https://github.com/discourse/discourse-math
and has a clone address of:
https://github.com/discourse/discourse-math.git
I added this to app.yml and rebuilt Discourse as described
above and, after I remembered you have to manually enable a
newly-installed plug-in, it works perfectly with my
test document in the Sand Box:
https://scanalyst.fourmilab.ch/t/test-of-mathjax/22
Changed the permissions on the Sand Box so Moderators can
read/post/reply as well as Administrators.
You can centre text by using the following antiquated HTML:
<div align="center">
This some text to be centred.
</div>
You can also wrap the text with <p> </p> if you wish. The HTML
sanitiser strips all class= and style= attributes, so you can't
use them. It's ugly, but it works.