This command adds a **device** into the pool. By default, the **device** will
not be added if it's already a part of a different pool, but the user will be
asked whether or not to remove the device from its pool. When multiple devices
are provided, all of them are added into the pool. If one of the devices
cannot be added into the pool for any reason, the add command will fail. If no
pool is specified, the default pool will be chosen. In the case of a non
existing pool, it will be created using the provided devices.

