README.md in test_server-0.4.1 vs README.md in test_server-0.5.0

@@ -42,9 +42,25 @@
 
     $ git clone https://github.com/dg-vrnetze/test_server
     $ gem package:gem
     $ gem install pkg/test_server-<version>
 
+### Required libraries and external programs
+
+* File Type detection
+
+  You need to install `libmagic` for filetype detection. This library uses the
+  same database as the linux `file`-command. The source for that library can be
+  found at `http://www.darwinsys.com/file/`.
+
+  On `Arch Linux` and `Debian` you need to install the `file`-package. On `Red
+  Hat` make sure the `file-libs`-package is installed.
+
+* Virus detection
+
+  You need to install `clamav` for virus detection. Make sure the clamav-daemon
+  is running (`clamd`) and has fresh virus patterns.
+
 ### Archlinux
 
 Install via `AUR`
 
 ```bash