Notify user if adding a class has a time conflict (a modal/popup should appear that notifies the user about the time conflict, but still give them the option to add a class.)

[Aslimmax]

Overview

When a user attempts to add a class that has a time conflict, the user should be notified about the time conflict, but should still allow them to keep the overlapped class.

Goal

Display an alert or modal about the time conflict. Should display which classes have a time conflict

Requirements

• Design an alert/modal
• Algorithm to do a linear search through the classes atom to determine if a time conflict exists

[kctoft]

Please see my recent PR, Add warning for scheduling conflict #100