title: align-self stretch not working?
body: <p>Hello I am practicing CSS flex boxes and everything is going good but when I tried to use align-self property all of its values work like flex-start , flex-end , center etc but the stretch one won't work here is the code </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>#flexcontainer {
    border: 3px solid black;
    display: flex;
    flex-wrap: wrap;
    height: 450px;
    justify-content: space-around;
    max-width: 500px;
    margin: 150px auto;
  }
  .flexitem {
    background: yellow;
    width: 48%;
    height: 115px;
    text-align: center;
    line-height: 115px;
  }
  .one {
    align-self: stretch;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div id="flexcontainer"&gt;
    &lt;div class="flexitem one"&gt;1&lt;/div&gt;
    &lt;div class="flexitem two"&gt;2&lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>