title: this.forceUpdate() not re-rendering dynamically created components
body: <p>Assume all the various components have been defined.</p>
  
  <p>In my react component, I want the button click to trigger the appending of a new <code>TextBox</code> component in my dynamically created <code>questions</code> component. When I tested the button click with <code>forceUpdate()</code>, a <code>TextBox</code> was successfully appended to <code>questions</code> but there was no apparent addition of a new <code>TextBox</code> element. I tested whether the component was actually re-rendering by using <code>&lt;h4&gt;Random number : {Math.random()}&lt;/h4&gt;</code> and it turns out the component was doing so, as the number changed every time I pressed the button.</p>
  
  <p>Is something being done wrong?</p>
  
  <pre><code>constructor (props) {
    super(props);
    this.questions = [];
    this.questions.push(&lt;TextBox key={this.questions.length}/&gt;);
    this.createTextBox = this.createTextBox.bind(this);
    this.loadTextBox = this.loadTextBox.bind(this);
  }
  
  createTextBox() {
    this.questions.push(&lt;TextBox key={this.questions.length}/&gt;);
    this.forceUpdate();
  }
  
  loadTextBox() {
    return (this.questions);
  }
  
  render() {
    return(
      &lt;div&gt;
        &lt;h4&gt;Random number : {Math.random()}&lt;/h4&gt;
        {this.loadTextBox()}
        &lt;ButtonToolbar className="add-question"&gt;
          &lt;DropdownButton bsSize="large" title="Add" id="dropdown-size-large" dropup pullRight&gt;
            &lt;MenuItem eventKey="1" onClick={this.createTextBox}&gt;Text Box&lt;/MenuItem&gt;
          &lt;/DropdownButton&gt;
        &lt;/ButtonToolbar&gt;
      &lt;/div&gt;
    );
  }
  </code></pre>