I Googled it. Found this in the documentation and followed the directions. It only takes a minute, assuming it works. Good luck!
SketchUp and .rbz files
The SketchUp 8 and newer allow you to install zipped Ruby files (.rbz) from within the product. If your plugin has a standard (.zip) extension, then you can just change the extension name from .zip to .rbz.
To install a SketchUp Ruby plugin script with the .rbz format:
We recommend logging into your computer as an admin before installing any Ruby scripts. This will make the installation go more smoothly and ensure that files get installed in the proper places.
Select Window > Preferences (Microsoft Windows) or SketchUp > Preferences (Mac OS X). The Preferences dialog box is displayed.
Click on Extensions. The Extensions panel is displayed.
Click on the Install Extension button. The Open dialog box is displayed.
Locate the Ruby zip file to install (.rbz).
Click on the Open button. The Ruby plugin appears in the list of extensions.