Add another time period and random time periods

[faram59]

Two suggestions:

1. Add the ability to add another time, I want to test what effect it has on my learning if I study for 50 minutes, review for ten minutes, and do half an hour of exercise or physical activity.
2. Andrew Huberman suggests pausing and reviewing randomly every 2 to 3 minutes, and also setting a random time mode for studying that randomly alarms at the user's desired interval and then gives the required amount of time (for example, one minute) to review.