Merge branch 'os-requirements' of /home/git/repositories/gitlab/gitlabhq

doc/install/requirements.md

 # Operating Systems
 
-## Linux
-
 GitLab is developed for the Linux operating system.
 
-GitLab officially supports (recent versions of) these Linux distributions:
+## GitLab officially supports
 
 - Ubuntu Linux
 - Debian/GNU Linux
 
-It should also work on (though they are not officially supported):
+## GitLab.com offers paid support for
 
-- Arch
+- Red Hat Enterprise Linux (RHEL)
 - CentOS
+- Oracle Linux
+
+## Not officially supported
+
+- Arch Linux
 - Fedora
 - Gentoo
-- RHEL
 
-## Other Unix Systems
+On the above distributions it is pretty easy to install GitLab yourself.
+
+## Unsupported Unix Systems
 
-There is nothing that prevents GitLab from running on other Unix operating
-systems. This means you may get it to work on systems running FreeBSD or OS X.
-**If you want to try, please proceed with caution!**
+There is nothing that prevents GitLab from running on other Unix operating systems.
+This means you may get it to work on systems running FreeBSD or OS X.
+If you want to do this, please be aware it could be a lot of work.
+Please consider using a virtual machine to run GitLab.
 
-## Windows
+## Other operating systems such as Windows
 
-GitLab does **not** run on Windows and we have no plans of supporting it in the
-near future. Please consider using a virtual machine to run GitLab.
+GitLab does **not** run on Windows and we have no plans of supporting it in the near future.
+Please consider using a virtual machine to run GitLab.
 
 
-# Rubies
+# Ruby versions
 
-GitLab requires Ruby (MRI) 1.9.3 and several Gems with native components.
-While it is generally possible to use other Rubies (like
-[JRuby](http://jruby.org/) or [Rubinius](http://rubini.us/)) it might require
-some work on your part.
+GitLab requires Ruby (MRI) 1.9.3 or 2.0+.
+While it is generally possible to use other Rubies
+(like [JRuby](http://jruby.org/) or [Rubinius](http://rubini.us/))
+it might require some work since GitLab uses several Gems that have native extensions.
 
 
 # Hardware requirements