Build From Source OSX (#3456)

* Update README.md

Added OS X steps to build from source

* Update README.md

Formating Fix

README.md

@@ -410,6 +410,22 @@ All contributions are welcome just send a pull request.  Jackett's framework all
 * Select Jackett.Console as startup project
 * Build/Start the project
 
+### OSX
+NOTE: msbuild is included in the mono release. 
+* Install Homebrew https://brew.sh
+* open terminal
+* brew install nuget mono
+* git clone https://github.com/Jackett/Jackett.git
+* cd Jackett/src
+* nuget restore Jackett.sln
+
+NOTE: if you get the error "NU1102: Unable to find package Microsoft.AspNetCore with version (>= 2.1.2)" while restoring packages, you'll need to install it manually.https://www.microsoft.com/net/download/thank-you/dotnet-sdk-2.1.302-macos-x64-installer then delete the entire project directory and restart from a new clone
+
+* msbuild Jackett.Console/Jackett.Console.csproj /t:Build /p:Configuration=Debug
+* curl -sS https://curl.haxx.se/ca/cacert.pem | cert-sync --user /dev/stdin
+* mono Jackett.Console/bin/Debug/JackettConsole.exe
+
+
 ### Linux
 
 ```bash