feat: add doc/signal-desktop.md

doc/signal-desktop.md

@@ -0,0 +1,54 @@
+# Signal Setup
+
+[source](https://www.linuxcapable.com/how-to-install-signal-on-debian-linux/)
+
+* update Debian's package index
+```
+sudo apt update && sudo apt upgrade
+```
+* install the Initial Required Packages For Signal Installation
+```
+sudo apt install dirmngr ca-certificates software-properties-common apt-transport-https curl --no-install-recommends
+```
+
+* download Signal Desktop APT Repository
+```
+curl -fsSL https://updates.signal.org/desktop/apt/keys.asc | gpg --dearmor | sudo tee /usr/share/keyrings/signal-desktop-keyring.gpg > /dev/null
+```
+
+* import the APT repository
+```
+echo "deb [arch=amd64 signed-by=/usr/share/keyrings/signal-desktop-keyring.gpg] https://updates.signal.org/desktop/apt xenial main" | sudo tee /etc/apt/sources.list.d/signal-desktop.list
+```
+
+* update to reflect the new additional repository
+```
+sudo apt update
+```
+
+*  install Signal package from Debian's APT repository
+```
+sudo apt install signal-desktop --no-install-recommends
+```
+
+* check the Signal version
+```
+signal --version
+```
+
+# Cleanup
+
+* first, remove the Signal Desktop application using the following command
+```
+sudo apt remove signal-desktop
+```
+
+* remove the repository using the following command
+```
+sudo rm /etc/apt/sources.list.d/signal-desktop.list
+```
+
+* remove the GPG key as follows
+```
+sudo rm /usr/share/keyrings/signal-desktop-keyring.gpg
+```