Allow other then ✓ to mark the open hour

[waviaei]

At the moment, the open hour is displayed using a tick-mark ✓ .
Allow user to choose other mark to display. My suggestion I have at the moment is circle ○.

For the UI, either:

• add ○ to dropdown list of when picking ✓ or - in each time slot; OR
• add a field in setting screen for "Icon to mark the open hour: [drop-down]"