[Question] How do I run this?

[frakman1]

Ruby novice here. How do I use this awesome tool?
I have Ruby 2.3.7p456 installed on my Mac.

I ran sudo gem install bundler to get bundler, then I ran bundler install from the root to install all dependencies. Then I went into the examples folder and ran:

ruby constant_autoloading_in_ruby_on_rails.rb
and got this error:

constant_autoloading_in_ruby_on_rails.rb:3:in `<main>': undefined method `center' for main:Object (NoMethodError)