minor update in the readme

Author: mackuba

README.md

@@ -15,11 +15,13 @@ Since version 0.5, Skyfall also supports connecting to [Jetstream](https://githu
 
 ## Installation
 
-From the command line:
+To use Skyfall, you need a reasonably new version of Ruby – it should run on Ruby 2.6 and above, although it's recommended to use a version that's still getting maintainance updates, i.e. currently 3.2+. A compatible version should be preinstalled on macOS Big Sur and above and on many Linux systems. Otherwise, you can install one using tools such as [RVM](https://rvm.io), [asdf](https://asdf-vm.com), [ruby-install](https://github.com/postmodern/ruby-install) or [ruby-build](https://github.com/rbenv/ruby-build), or `rpm` or `apt-get` on Linux (see more installation options on [ruby-lang.org](https://www.ruby-lang.org/en/downloads/)).
 
-    gem install skyfall
+To install the gem, run the command:
 
-Or, add this to your `Gemfile`:
+    [sudo] gem install skyfall
+
+Or add this to your app's `Gemfile`:
 
     gem 'skyfall', '~> 0.6'