Description

Created a check flag for pomodoros to verify that a pomodoro has already been reminded.

Issues

Closes #380

Select one or more of the following:

[x] Bug fix (non-breaking change which fixes an issue)
[x] New feature (non-breaking change which adds functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
[ ] Other (describe below)

Changed check flags, verified they properly set, and modified pomodoro flag after 20 minutes.

[x] All local commits have been pushed to remote
[x] All changes on the base branch have been merged into this branch, either by rebase or merge
[x] My code is PEP-8 compliant (excluding maximum line length, keep that to 100ish characters)
[x] I have performed a self-review of my own code
[x] I have commented my code, particularly in hard-to-understand areas
[x] I have added Google Docstrings for all new functions/methods
[ ] I have made corresponding changes to the documentation