<div class="form-group" *ngFor="let url of urls; let id = index; trackBy:customTrackBy">
<label for="username">Url</label>
<div class="input-group">
<div class="form-group" *ngFor="let url of urls; let id = index; trackBy:customTrackBy">
<label for="username">Url</label>
<div class="input-group">
<span class="input-group-btn">
<button *ngIf="displayAddField(id)" (click)="addField()" class="btn btn-default" type="button">+</button>
<button *ngIf="displayRemoveField(id)" (click)="removeField(index)" class="btn btn-default" type="button">-</button>
<span class="input-group-btn">
<button *ngIf="displayAddField(id)" (click)="addField()" class="btn btn-default" type="button">+</button>
<button *ngIf="displayRemoveField(id)" (click)="removeField(index)" class="btn btn-default" type="button">-</button>