title: Merge data with posts in Jekyll
body: <p>I have a directory <code>_posts</code> where I store articles.  I also have a data file <code>_data/teasers.yml</code> that contains information about articles posted on other sites.  I'm trying to avoid republishing content when I could include a teaser and link back to the original location of the article.</p>
  
  <p>I'd like to combine both teasers and posts so I can loop through them in chronological order.  Is this possible with Jekyll/Liquid?</p>
  
  <h2>Example teaser</h2>
  
  <pre><code>- title: A harmonious future for profiles and pine
    date: 2017-05-09
    url: https://www.example.com/articles/a-harmonious-future-for-profits-and-pine/
  </code></pre>
  
  <h2>Example template</h2>
  
  <pre><code>{% assign posts = site.posts %}
  {% assign teasers = site.data.teasers %}
  
  # how can I combine these???
  {% assign stories = posts | concat: teasers %}
  
  {% for story in stories %}
    {{ story.title }}
  {% endfor %}
  </code></pre>
  
  <p>I'm using Jekyll 3.2.x on a mac.</p>