A singleton is a class that has only one instance in an application.
"MooseX::Singleton" lets you easily upgrade (or downgrade, as it were)
your Moose class to a singleton.

All you should need to do to transform your class is to change "use Moose"
to "use MooseX::Singleton". This module uses metaclass roles to do its
magic, so it should cooperate with most other "MooseX" modules.