At the risk of diluting the important message about kernel tunables, there’s a second consideration: the present script only creates swap on a low-RAM machine. I think that’s a mistake, both because swap is still useful in maximising the usefullness of RAM, but more importantly because it will cause trouble if someone creates their Discourse on a large-RAM machine, for speed or convenience, and then downsizes it to small-RAM.
The setup should create swap in all cases (unless there’s already enough.) It’s valid and sometimes useful to have multiple swapfiles.