How to install a plugin on Discourse-hosted-Discourse?

You may want to move to self hosting; it’s unlikely we will include that particular plugin any time soon.

Also reminder, you can simply do checklists using emoji and edits, e.g:

  • :ballot_box_with_check: Something I finished

  • :black_square_button: Something I haven’t finished

which is

- :ballot_box_with_check: Something I finished

- :black_square_button: Something I haven't finished