Second time alert

[Lucianohartm]

• I've verified that I use the latest version of the add-on by redownloading it from AnkiWeb
• I've verified that I use the latest version of Anki by checking at https://apps.ankiweb.net#download
• I've checked if anyone else suggested this feature before by looking through the issue reports.

It's just a silly recommendation, but that I thought it would be useful. I second time alert or the possibility to set as many alerts you want during the time you limit for each card would be helpful if you want to make sure to maintain your consistency through the entire time.