diff --git a/System-configuration.md b/System-configuration.md
index e5dfaac..357fa35 100644
--- a/System-configuration.md
+++ b/System-configuration.md
@@ -1,6 +1,22 @@
 # System configuration
 This page contains steps to set up a server to successfully run **ReCodEx**. Before final release most of them will be included in instalation script or listed as dependecies to binary package (`rpm` or `deb`). This page is mostly oriented to Red Hat based Linux distros (like RHEL, Centos or Fedora), but I'll try to keep updated information about Debian too. Before starting, make sure you have completed basic OS installation and set up, including users and logins, SSH, Git, firewall, etc.
 
+## Common
+**Add _testing_ repositories to Debian OS**
+- Create file `/etc/apt/apt.conf` with content
+```
+APT::Default-Release "stable";
+```
+- Add testing repos to `/etc/apt/sources.list`
+```
+deb http://ftp.cz.debian.org/debian/ testing main contrib non-free
+deb-src http://ftp.cz.debian.org/debian/ testing contrib non-free
+```
+- Install packages with `-t testing` option. For example
+```
+$ sudo apt-get -t testing install gcc
+```
+
 ## Worker
 Worker requirements are written in this section. Some parts of this guide may be different for each type of worker, for example Compiler principles worker is not fully covered here.
 
@@ -55,4 +71,6 @@ $ sudo apt-get install mono-complete
 Free Pascal compiler 3.0.0 can be downloaded as `rpm` packages from [official website](http://www.freepascal.org/down/x86_64/linux-austria.var). In Debian, this version is [expetimental](https://packages.debian.org/experimental/fpc-3.0.0), but seems to be stable enough.
 
 **Java**
-_**TODO**_
\ No newline at end of file
+_**TODO**_
+
+## WebApp