如何在meteor中的帖子中插入用户名

meteor add accounts-base accounts-password

Posts = new Mongo.Collection('posts');

Posts.attachSchema(new SimpleSchema({
  title: {
    type: String,
    label: "Title",
    max: 200
  },
  content: {
    type: String,
    label: "Content",
    max: 2000
  },
  username: {
    type: String,
    label: "Username",
    autoValue: function() {
      if (this.isInsert) {
        return Meteor.user().username;
      }
    },
    autoform: {
      type: "hidden"
    }
  }
}));

<template name="postForm">
  {{#autoForm collection=Posts id="postForm" type="insert"}}
    {{> afQuickField name='title'}}
    {{> afQuickField name='content'}}
    {{> afQuickField name='username' type='hidden'}}
    <button type="submit" class="btn btn-primary">Submit</button>
  {{/autoForm}}
</template>

Template.postList.helpers({
  posts: function() {
    return Posts.find();
  },
  getUsername: function(userId) {
    var user = Meteor.users.findOne(userId);
    if (user) {
      return user.username;
    }
  }
});

<template name="postList">
  <ul>
    {{#each posts}}
      <li>
        <strong>{{title}}</strong> - {{getUsername createdBy}}
      </li>
    {{/each}}
  </ul>
</template>