Add ng-bootstrap, implement task form modal window

src/app/task-form/task-form.component.ts

@@ -1,4 +1,5 @@
 import { Component, OnInit, Input } from '@angular/core';
+import { NgbActiveModal } from '@ng-bootstrap/ng-bootstrap';
 import { BackendService, Task } from '../services/backend.service';
 
 @Component({
@@ -15,7 +16,7 @@ export class TaskFormComponent implements OnInit {
     public task: Task;
     private submitted: boolean;
 
-    constructor(private backendService: BackendService) { }
+    constructor(private backendService: BackendService, private activeModalService: NgbActiveModal) { }
 
     ngOnInit(): void {
         if (this.task !== null && this.task !== undefined) {
@@ -35,5 +36,6 @@ export class TaskFormComponent implements OnInit {
             this.backendService.postTask(this.task);
         }
         this.submitted = true;
+        this.activeModalService.close();
     }
 }