Added support for Laravel 5.8

Porting getMinutesOn() and getHoursOn() to the model itself (rennokki#10

)

* Ported getHoursOn() and getMinutesOn() directly into the schedule model.

* Updated the tests.

* Apply fixes from StyleCI (rennokki#11)

Removed nesbot/carbon. (rennokki#9)

Support for Laravel 5.7 (rennokki#8)

* Renamed codecov.yaml

* Using $guarded.

* Support for Laravel 5.7

Consistency fixes with hints. (rennokki#5)

* Consistency fixes.

* Apply fixes from StyleCI (rennokki#6)

Apply fixes from StyleCI (rennokki#4)

Apply fixes from StyleCI (rennokki#3)

Added Codecov badge. [skip ci]

Merge pull request rennokki#1 from rennokki/test-units

Added test units.

The vendor:publish command had wrong paths.