add supported tools

README.md

@@ -6,6 +6,14 @@ universal package manager
 
 A simple wrapper tool for the most used package management tools. It uses the same subcommands as FreeBSD' `pkg` (hence the name) so I don't need to memoize all the other syntaxes.
 
+## supported package systems:
+
+- yum and dnf - CentOS
+- zypper - Suse
+- pacman - ArchLinux
+- xbps - Voidlinux
+- pkg - FreeBSD
+
 ## Usage
 
 Copy the file pkg to some suitable location. Please note: Bash is required.