Corrections in SchedulesController

- Controler file name pluralized
- Load and authorization fixed and improved
- Consider that save can fail in create action
- Eliminate unnecessary if in update action
- Ability and tests related to the schedules link in the admin sidebar fixed

app/views/admin/schedule/_event.html.haml

@@ -1,14 +0,0 @@
-- cells_length = event.event_type.length / EventType::LENGTH_STEP
-/ this height fits the room cells
-- height = (cells_length * 58) - 23
-/ subtracting the padding before calculate the number of lines
-- lines = (height - 7) / 23
-- color = event.track.try(:color).present? ? event.track.try(:color) : 'FFFFFF'
-.schedule-event{ style: "height: #{height}px;  background-color: #{color}; color: #{contrast_color(color)}", |
-                 id: "event-#{event.id}", |
-                 event_id: event.id, |
-                 length: cells_length, |
-                 event_schedule_id: event_schedule_id }
-  .schedule-event-text{ style: "-webkit-line-clamp: #{lines}; height: #{lines * 23}px;"}
-    %span.schedule-event-delete-button{ onclick: "Schedule.remove(\'event-#{event.id}\');" } X
-    = event.title