Add installation instruction for FreeBSD (grouzen#47)

* Add installation instruction for FreeBSD

* Address PR comments

Author: grouzen

README.md

@@ -58,6 +58,14 @@ It is available via [AUR](https://aur.archlinux.org/packages/framework-tool-tui)
 sudo pacman -S framework-tool-tui # Install from archlinuxcn
 ```
 
+### 😈 FreeBSD
+
+
+It is available in [FreeBSD ports](https://www.freshports.org/sysutils/framework-tool-tui/)
+```sh
+pkg install framework-tool-tui
+```
+
 ## :man: Run
 
 It needs to be running with root privileges to access hardware controls.