title: How are entire directory trees "required" in Ruby?
body: <p>A lot of the questions and resources on the web have given ways to require a directory of files (e.g. <code>Dir["/path/to/directory/*.rb"].each {|file| require file }</code>). What I haven't been able to find however are ways to require whole trees of files, a.k.a directories w/ more directories and files in them. On top of that, a lot of the methods I found (including the one I previously mentioned) online have returned "Cannot load such file" errors. What's the most efficient way to recursively require files throughout file trees that's compatible w/ the latest Ruby version?</p>