The history of grids in memory, for development and tests: it lasts as long as the node, and every grid of the node shares it. Not for production.
Start it in your supervision tree (or in test_helper.exs):
children = [Masu.History.Memory, ...]
Summary
Functions
Returns a specification to start this module under a supervisor.
See Supervisor.
@spec clear() :: :ok
Forgets every entry.