ngModel and scope inheritance

edit.html

<div ng-controller="EditController">
  <span>{{message.content}}</span>
  <div ng-if="userIsAdmin">
    <span>Edit Message</span>
    <input ng-model="message.content"/>
  </div>
</div>

edit_controller.js

app.controller('EditController', function($scope) {
  $scope.userIsAdmin = true;
  $scope.message = {
    content: 'Redact me'
  };
});