Consider dropping sudo from "sudo gem install" in example

[nevir]

sudo gem install is harmful in a lot of setups.

• You end up writing root-owned files to userland dirs for any sort of managed Ruby environment (chruby, rvm, rbenv, etc).
• Related to above, it's a real pain to blow away the gem, or a ruby vm when you've got mixed ownership over the gems directory.
• Gems can run arbitrary code on the user's machine during install; not great practice to promote that as the default behavior.
• Depending on the user's setup, sudo may be dropping env vars such as GEM_HOME, placing gems into undesired locations.

etc.