README: update for Homebrew lua instructions

[DomT4]

Re #554.

[szymonkaliski]

Is this change really needed? I just reinstalled Lua with latest homebrew version, and haven't change anything, and could install all mjolnir.* things I use...? (that's only about ~/.luarocks/config.lua vs /usr/local/etc/luarocks52/config-5.2.lua, everything else is obviously needed) :)

[DomT4]

There's not much controversial here:

brew install luarocks = Removed because that formula no longer exists. mkdir -p ~/.luarocks = Removed because the new Luarocks has hardcoded config dirs to facilitate side-by-side usage. echo 'rocks_servers = { "http://rocks.moonscript.org" }' > /usr/local/etc/luarocks52/config-5.2.lua = Said new config dir for the standard Lua installation.

[szymonkaliski]

Yeah, I just prefer keeping settings like that in ~/... instead in /usr/..., maybe put both as alternatives?

[szymonkaliski]

Actually on my system there's already something in there:

> cat /usr/local/etc/luarocks52/config-5.2.lua
rocks_trees = {
   { name = [[system]], root = [[/usr/local]] }
}

And if you're using > you're overwriting that...

[DomT4]

maybe put both as alternatives?

Can't. Doesn't play nicely with the potential for multiple Lua/Luarocks setups. etc is a fairly widely accepted sysconfdir. Luarocks via Homebrew should actually ignore a conf in the $HOME prefix now.

Actually on my system there's already something in there:

Yes, Homebrew put it there.

And if you're using > you're overwriting that...

Indeed. I'd much prefer to use >>. I didn't write the original README though, and the original README is written so it'd overwrite anything that was previously in that file.

[thesoftwarephilosopher]

@DomT4 The original readme was pointing to a presumably non-existent file, and the update is pointing to a confirmed-existing file, so it should use >>.

[DomT4]

Cool. Thanks for the feedback. Will change.

[thesoftwarephilosopher]

Thanks.