Download GemPluginImport.js
to wherever you keep your user scripts like _assets/scripts
Open the QuickAdd settings and press the Manage Macros
button
Add a new macro named something like ImportGem
and press configure
Select the name of your user script and press Add
Press the Template
button and fill it out however you want, using the template provided.
Then on the main QuickAdd settings page, add a new Macro choice and select the name of your script