Still need to figure out how get the email notification thing to work. Because I also don't know how to test whether the app will work over the span of a week (aka keep my server running for a week to see if it updates over time), I've decided that an email notification will send when user inputs an entry and the difference between purchase_date and exp_date is less than 1, just to check at least if it works.

And yet, I still need to figure even THAT out.