Get rid of `sudo` in `sudo gem install` on docs

docs/getting-started/index.md

@@ -54,7 +54,7 @@ quickest and easiest way to distribute Vagrant to the masses, and it can be inst
 just as easily:
 
 {% highlight bash %}
-$ sudo gem install vagrant
+$ gem install vagrant
 {% endhighlight %}
 
 ## Your First Vagrant Virtual Environment

index.md

@@ -17,7 +17,7 @@ the [getting started guide](/docs/getting-started/index.html), the
 ## Your First Vagrant Virtual Environment
 
 {% highlight bash %}
-$ sudo gem install vagrant
+$ gem install vagrant
 $ vagrant box add base http://files.vagrantup.com/base.box
 $ vagrant init
 $ vagrant up