gistfile1.js

    render: function() {
      var stories = this.state.map((story) => {
          return (
            <ReactCSSTransitionGroup transitionName="Story">
              <Story key={story.id} story={story} />
            </ReactCSSTransitionGroup>
          )
      })

      return (
          <div>
            {stories}
          </div>
      )
    }
  });