Gets a single monitor
the key to identify the monitor
The monitor if exists, or null
Gets all monitors, or empty [], if no monitors are available
Inserts a monitor
the monitor to be stored. If monitor exists already in the repo
the insert method rejects the promise with a message, i.e.
Model with key '[${monitor.key}]' already exists
Removes a monitor
The key for the monitor to be removed. If monitor does not exists, remove just ignores the actions and does not reject or throws any error
The repository for monitor storing