title: Lines have disappeared from flextables
body: <p>Looking at the <code>flextable</code> documentation <a href="https://davidgohel.github.io/flextable/articles/format.html" rel="nofollow noreferrer">here</a> for <code>flextable_0.5.0</code>, there should be lines on my flextable, but I don't get any.</p>
  <h1>Code:</h1>
  <pre><code>myft &lt;- flextable(head(iris))
  myft
  </code></pre>
  <h1>Output:</h1>
  <p><a href="https://i.stack.imgur.com/c25NJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/c25NJ.png" alt="enter image description here" /></a></p>
  <h1>Expected Output:</h1>
  <p><a href="https://i.stack.imgur.com/haMqW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/haMqW.png" alt="enter image description here" /></a></p>
  <p>I should be able to add lines if I want them using this code:</p>
  <pre><code>myft &lt;- flextable(head(iris)) %&gt;% 
    border_outer(border = fp_border(color=&quot;black&quot;, width = 1))
  myft
  </code></pre>
  <p>But no borders appear. I assume this is a bug? Or have the commands changed but the documentation not been updated?</p>
  <p>In the mean time, is there a way to roll back to the previous version?</p>
  <h1>Edit:</h1>
  <p>Just re-isntalled version <code>0.4.6</code> and <code>0.4.5</code> and I'm having the same issue so not sure what's going on. I'm using R version <code>3.5.2</code>. I wasn't having this issue yesterday before I upgraded to <code>0.5.0</code>.</p>
  <h1>Edit 2:</h1>
  <p>The latest update (<code>0.5.1</code>) has resolved the issue :) Thanks @DavidGohel</p>