How to change a build version in Sublime Text 3

Here's what I did:

1. select "Sublime Text" > "Preferences" > "Browse Packages ..."

   (this opens ~/Library/Application Support/Sublime Text 3/Packages)

2. open the User directory (create it if it doesn't exist)

3. inside User create a file Ruby.sublime-build with the following content (adjust the path):

   {
       "cmd": ["/your/path/to/bin/ruby", "$file"],
       "file_regex": "^(...*?):([0-9]*):?([0-9]*)",
       "selector": "source.ruby"
   }
   

Your directory structure should look like this:

~/
  Library/
    Application Support/
      Sublime Text 3/
        Packages/
          User/
            Ruby.sublime-build