add documentation

README.md

@@ -9,6 +9,7 @@ Requirements
 * PHP
 * /bin/sh
 * GCC
+* whiptail
 * wget
 * make
 
@@ -16,6 +17,8 @@ Installation
 ------------
 
 ```
+$ sudo apt install gcc whiptail wget make
+$ sudo apt install <php stuff>
 $ git clone https://gitnet.fr/deblan/vhost-manager.git
 $ cd vhost-manager
 $ make