Automatically transferring themes… question

I’m going to attempt to follow these instructions given here.

ask.discourse.com is telling me that the getting into rails part should actually be:

cd /var/discourse
./launcher enter app
rails c

Or that I should put rails runner "..." around the command:

rails runner "UserOption.where(theme_ids: [23]).update_all(theme_ids: [56])"

I've never done any rails commands before so I'm quite nervous.