Update stack information and remove redundancy

Former-commit-id: 645412b5

README.md

@@ -19,7 +19,6 @@ To see how GitLab looks please see the [features page on our website](https://ab
 - Each project can also have an issue tracker, issue board, and a wiki
 - Used by more than 100,000 organizations, GitLab is the most popular solution to manage Git repositories on-premises
 - Completely free and open source (MIT Expat license)
-- Powered by [Ruby on Rails](https://github.com/rails/rails)
 ## Hiring
@@ -75,11 +74,11 @@ Instructions on how to start GitLab and how to run the tests can be found in the
 GitLab is a Ruby on Rails application that runs on the following software:
-- Ubuntu/Debian/CentOS/RHEL
+- Ubuntu/Debian/CentOS/RHEL/OpenSUSE
 - Ruby (MRI) 2.3
 - Git 2.8.4+
 - Redis 2.8+
-- MySQL or PostgreSQL
+- PostgreSQL (preferred) or MySQL
 For more information please see the [architecture documentation](https://docs.gitlab.com/ce/development/architecture.html).