title: Lodash create collection from duplicate object keys
body: <p>I have the following structure:</p>
  
  <pre><code>var output = [{
      "article": "BlahBlah",
      "title": "Another blah"
  }, {
      "article": "BlahBlah",
      "title": "Return of the blah"
  }, {
      "article": "BlahBlah2",
      "title": "The blah strikes back"
  }, {
      "article": "BlahBlah2",
      "title": "The blahfather"
  }]
  </code></pre>
  
  <p>From the above using an elegant lodash one-liner, I need to create the following structure.</p>
  
  <pre><code>var newOutput = [{
      "article": "BlahBlah",
      "titles": ["Another blah", "Return of the blah"]
  }, {
     "article": "BlahBlah2",
     "titles": ["The blah strikes back", "The blahfather"]
  }]
  </code></pre>
  
  <p>Help as always, is greatly appreciated.. A huge plus for an explanation for how a solution would work.</p>