Merge pull request #3429 from opf/fix/add_system_requirements

Add system requirements

doc/operation_guides/system_requirements.md

@@ -0,0 +1,52 @@
+# System Requirements
+
+__Note__: The configurations described below are what we use and test against.
+This means that other configurations might also work but we do not
+provide any official support for them.
+
+## Server
+
+### Hardware
+
+* __Memory:__ 512 MB (1024 recommended)
+* __Free disc space:__ 300 MB (4096 recommended)
+
+### Operating System
+
+| Distribution (64 bits only)     | Identifier   | init system |
+| :------------------------------ | :----------- | :---------- |
+| Ubuntu 14.04 Trusty             | ubuntu-14.04 | upstart     |
+| Debian 8 Jessie                 | debian-8     | systemd     |
+| Debian 7 Wheezy                 | debiani-7    | sysvinit    |
+| CentOS/RHEL 7.x                 | centos-7     | systemd     |
+| CentOS/RHEL 6.x                 | centos-6     | upstart     |
+| Fedora 20                       | fedora-20    | sysvinit    |
+| Suse Linux Enterprise Server 12 | sles-12      | sysvinit    |
+
+### Dependencies
+
+* __Runtime:__ [Ruby](https://www.ruby-lang.org/en/) Version 2.1.6
+* __Webserver:__ [Apache](http://httpd.apache.org/)
+  or [nginx](http://nginx.org/en/docs/)
+* __Application server:__ [Phusion Passenger](https://www.phusionpassenger.com/)
+  or [Unicorn](http://unicorn.bogomips.org/)
+* __Database:__ [MySQL](https://www.mysql.com/) Version >= 5.6
+  or [PostgreSQL](http://www.postgresql.org/) Version >= 9.1
+
+Please be aware that the dependencies listed above also have a lot of
+dependencies themselves.
+
+## Client
+
+OpenProject supports the latest versions of the major browsers. In our
+strive to make OpenProject easy and fun to use we had to drop support
+for some older browsers.
+
+* [Mozilla Firefox](https://www.mozilla.org/en-US/firefox/products/) (Version >= 31 ESR)
+* [Microsoft Internet
+  Explorer](http://windows.microsoft.com/en-us/internet-explorer/download-ie) (Version >= 10)
+* [Google Chrome](https://www.google.com/chrome/browser/desktop/)
+
+## Screen reader support (accessibility)
+
+* [JAWS](http://www.freedomscientific.com/Products/Blindness/JAWS) >= 14.0