Core: Manager
Leverage's manager is the foundation on which any application is built. All Leverage units are given to the manager in order to compose them.
The manager's public interface is rather small. In most cases, you will only need to use its add() method.
Returns a new instance of Manager.
Add a Unit to the manager.
Unit can be any valid Leverage unit.
Add a Plugin to the manager.
Add a Service to the manager.
Add a Component to the manager.
Add a Middleware to the manager.