[+] Encapsulate addCallback()

src/logic/course.ts

@@ -65,6 +65,16 @@ export class Assignment
         return this.complete == 'Complete';
     }
 
+    /**
+     * Add callback
+     *
+     * @param callback
+     */
+    addCallback(callback: () => void)
+    {
+        this.updateCallbacks.push(callback);
+    }
+
     /**
      * Mark as read
      */