Add Arch Linux installation instructions

[arjan-s]

As requested in #63

[binwiederhier]

Awesome thanks

[binwiederhier]

Does this auto update or do you need to manually update the aur package thingy?

[arjan-s]

It depends. If one uses an AUR helper, it will keep the package up to date. If one chooses to install a package manually, updating is up to the user.

[binwiederhier]

Oh I should have been more clear, sorry for not knowing this. The PKGBUILD file (https://aur.archlinux.org/cgit/aur.git/tree/PKGBUILD?h=ntfysh-bin), do you have to manually update this on every new version? Cause I iterate quite quickly and I'd like to reduce other people's load, if I can do it or it happens automatically it's probably easier. I don't know how much you mind.

[arjan-s]

Oh right! Sorry, I misinterpreted your question.
Updating the PKGBUILD is manual labor (might script it away at some point though). I'm happy to do it, as I use it actively myself and also like to stay up to date on stuff I'm using. But if you prefer maintaining it yourself, I'm happy to surrender maintainership.

[binwiederhier]

Nah it's better if someone maintains it that actually knows what they are doing. Just let me know if you stop using it and then I'll jump in.

Thank youfl for your help!!!