Add instructions for usage of beta builds

docs/app/beta.md

@@ -0,0 +1,41 @@
+---
+title: Installing the beta build
+parent: App
+nav_order: 6
+---
+
+# Installing the beta build
+
+The beta build of the `gitmastery` CLI (known as `gitmastery-beta`) is able to be used alongside the stable release. The installation rules are listed below:
+
+## Debian/Ubuntu
+
+```bash
+echo "deb [trusted=yes] https://git-mastery.github.io/gitmastery-beta-apt-repo any main" | \
+  sudo tee /etc/apt/sources.list.d/gitmastery-beta.list > /dev/null
+sudo apt install software-properties-common
+sudo add-apt-repository "deb https://git-mastery.github.io/gitmastery-beta-apt-repo any main"
+sudo apt update
+sudo apt-get install gitmastery-beta
+```
+
+## Arch
+
+Use an AUR helper to install `gitmastery-beta-bin`. For example using yay:
+
+```bash
+yay -S gitmastery-beta-bin
+```
+
+Alternatively, you can build the `PKGBUILD` yourself following the [instructions on the Arch wiki](https://wiki.archlinux.org/title/Arch_User_Repository#Installing_and_upgrading_packages).
+
+## macOS
+
+```bash
+brew tap git-mastery/gitmastery-beta
+brew install gitmastery-beta
+```
+
+## Windows
+
+Download the `gitmastery-beta.exe` file from the [release page](https://github.com/git-mastery/app/releases). Follow similar instructions to the [stable release installation](https://git-mastery.org/companion-app/index.html#preparation-recommended-install-and-configure-the-git-mastery-app) after.