title: UITableView insertRows(at: indexPath) returns error of invalid number of rows
body: <p>I have a <code>tableView</code> which is supposed to display an array of images.
  The array is already filled before with 5 items and I need to use <code>insertRows</code> to fill my <code>tableView</code>. The problem is I receive the error below:</p>
  
  <blockquote>
    <p>Invalid update: invalid number of rows in section 0. The number of
    rows contained in an existing section after the update (5) must be
    equal to the number of rows contained in that section before the
    update (5), plus or minus the number of rows inserted or deleted from
    that section (1 inserted, 0 deleted) and plus or minus the number of
    rows moved into or out of that section (0 moved in, 0 moved out).</p>
  </blockquote>
  
  <p>My code is as below:</p>
  
  <pre><code>override func numberOfSections(in tableView: UITableView) -&gt; Int {
      return 1
  }
  
  override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -&gt; Int {
      return images.count
  }
  
  override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -&gt; UITableViewCell {
  
      let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! ImagesTableViewCell
      tableView.beginUpdates()
      tableView.insertRows(at: [IndexPath(row: 0, section: 0)], with: .automatic)
      cell.cellImageView?.image = UIImage(data: images[indexPath.row]!)
      tableView.endUpdates()
  }
  </code></pre>
  
  <p>I appreciate for any clue to solve this issue.</p>