GUS requires that all plugins be registered prior to use. This allows for close auditing of the environment in which the plugin operated and ensures that changes within a plugin do not go unnoticed. When you attempt to use a plugin that has not been registered, ga will respond with an error:

USER ERROR: GUS::Supported::Plugin::InsertControl has never been registered.
Please use 'ga +create GUS::Supported::Plugin::InsertControl --commit'

You must then use the command provided to register the plugin. In this case:

$ ga +create GUS::Supported::Plugin::InsertControl --commit

If a plugin changes since being registered, you may receive a similar error, requesting that you use the ga +update ... command.