add duration popover

src/app/shared/popover/group-duration/group-duration.page.ts

@@ -0,0 +1,15 @@
+import { Component, OnInit } from '@angular/core';
+
+@Component({
+  selector: 'app-group-duration',
+  templateUrl: './group-duration.page.html',
+  styleUrls: ['./group-duration.page.scss'],
+})
+export class GroupDurationPage implements OnInit {
+
+  constructor() { }
+
+  ngOnInit() {
+  }
+
+}