表的角度Http get方法

我是angular的新手,我试着弄清楚它是如何工作的。我试图从API中为我的表提取数据。

import { Component } from '@angular/core';
import { Http } from '@angular/http';
import 'rxjs/add/operator/map'; 
@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
class AppComponent {
  people: any;
  constructor(http: Http) {
    http.get('https://jsonplaceholder.typicode.com/todos')
      .map(res => res.json())
      .subscribe(people => this.people = people);
  }
}

interface people {
  userId:number;
  id:number;
  title:string;
  completed:boolean;

这个Html代码块

<tr *NgFor="let people of peoples">
              <td>{{people.userId}}</td>
              <td>{{people.id}}</td>
              <td>{{people.title}}</td>
              <td>{{people.completed}}</td>

我哪里做错了?任何建议都非常有用。