Update Prerequisites

[Lelith]

Hi there,
i just run into the stupid error that i did not have imagemagick installed on my local machine. And then directly run into the error on media upload. Would be cool if you could add all of these packages that are needed for running the app fully on a local machine. Just as a time saver ;)

lg leli

[ook]

Hi @Lelith , the problem is that Publify deal only with gems, and in the case of minimagick, rely on a separated library: imagemagick.

The move I propose is to add hints in Readme.md and rewrite https://github.com/publify/publify/wiki/Installing-Typo#WhatYouNeed
Does sound it ok for you?

[mvz]

Non-gem dependencies are now listed in the README. That seems the sensible place to have them.