Add command line for installing on Ubuntu/Raspbian OS (#404)

* Add command line for installing on Ubuntu/Raspbian OS

* Raspbian was the old name, now it is Raspberry OS

* Update README.md

README.md

@@ -4,6 +4,7 @@ FusionPBX Install
 A quick install guide & scripts for installing FusionPBX. It is recommended to start with a minimal install of the operating system. Notes on further tweaking your configuration are at end of the file.
 
 ## Operating Systems
+
 ### Debian
 Debian is the preferred operating system by the FreeSWITCH developers. It supports the latest video dependencies and should be used if you want to do video mixing. Download Debian at https://cdimage.debian.org/cdimage/release/current/
 
@@ -11,6 +12,13 @@ Debian is the preferred operating system by the FreeSWITCH developers. It suppor
 wget -O - https://raw.githubusercontent.com/fusionpbx/fusionpbx-install.sh/master/debian/pre-install.sh | sh;
 cd /usr/src/fusionpbx-install.sh/debian && ./install.sh
 ```
+
+### Ubuntu and Raspberry OS
+```sh
+wget -O - https://raw.githubusercontent.com/fusionpbx/fusionpbx-install.sh/master/ubuntu/pre-install.sh | sh;
+cd /usr/src/fusionpbx-install.sh/ubuntu && ./install.sh
+```
+
 ### Devuan
 If you like Debian but rather not bother with systemd, Devuan is a "drop in" replacement.
 Devuan ASCII is based on Stretch, so you will find most of the same packages available.