from, go back to Machinist module for more information.
Defines a state transition with the given
state, and the list of options
[to: new_state, event: event]
from 1, to: 2, event: "next"
It's also possible to define a
from any state transition to another specific one, by just passing an underscore variable in place of a real state value
from _state, to: :expired, event: "enrollment_expired"