Consider dropping sudo from "sudo gem install" in example

`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.