Make sure to use date objects everywhere where dealing with dates

src/models/taskAssignee.js

@@ -1,9 +1,14 @@
 import AbstractModel from './abstractModel'
 
 export default class TaskAssigneeModel extends AbstractModel {
+    constructor(data) {
+        super(data)
+        this.created = new Date(this.created)
+    }
+
     defaults() {
         return {
-            created: 0,
+            created: null,
             user_id: 0,
             task_id: 0,
         }