wrote all course/schedule background messages with handlers

src/shared/types/UserSchedule.ts

@@ -7,11 +7,9 @@ import { Course } from './Course';
 export class UserSchedule {
     courses: Course[];
     name: string;
-    creditHours: number;
 
     constructor(schedule: Serialized<UserSchedule>) {
         this.courses = schedule.courses.map(c => new Course(c));
-        this.creditHours = this.courses.reduce((acc, course) => acc + course.creditHours, 0);
         this.name = schedule.name;
     }