Added macOS installation steps

Installation.md

@@ -10,6 +10,19 @@ Radarr is now installed as a service set to auto start, check that it is running
 
 Don't forget to use UNC paths like `\\Server\Share` instead of mapped network drives like `M:\Movies`.
 
+
+### macOS ###
+
+* Install [Homebrew](https://brew.sh)
+* Install latest mono frameworks: brew install mono
+* Download release to desired folder (cd to that folder then run this command): curl -L -O $( curl -s https://api.github.com/repos/Radarr/Radarr/releases | grep linux.tar.gz | grep browser_download_url | head -1 | cut -d \" -f 4 )
+* Expand the file: tar -xvzf Radarr.develop.*.linux.tar.gz
+* Remove the archive: rm Radarr.develop.*.linux.tar.gz
+* Move into the new directory: cd Radarr
+* Start with: mono Radarr.exe
+* Optionally use screen, cd into the Radarr directory, use "screen", then "ls" to verify the directory, then "mono Radarr.exe", control+A+d to detach from the screen.
+
+
 ### Debian / Ubuntu ###
 
 Install dependencies: