Flex align bottom

HTML

<link rel="stylesheet" href="https://milligram.github.io/css/milligram.min.css">
<section class="post" id="post-<?php the_ID(); ?>">

			<article class="entry">

				<h2><?php the_title(); ?></h2>

				<?php the_content(); ?>

				<div class="container-fluid container">
					<div class="row">
						<div class="column">column
              <br ><br ><br ><br ><br ><br ><br ><br ><br >
            </div>
						<!-- should be aligned to the bottom -->
						<div class="column">
              <div class="col-bottom">column</div>
            </div>
					</div>
				</div>

			</article>

		</section>

CSS

.column {
  border: 1px solid red;
}
.col-bottom {
  border: 3px solid blue;
}




/*!
 * Milligram v1.1.0
 * http://milligram.github.io
 *
 * Copyright (c) 2016 CJ Patoilo
 * Licensed under the MIT license
*/


html {
  box-sizing: border-box;
  font-size: 62.5%;
}

body {
  color: #606c76;
  font-family: "Roboto", "Helvetica Neue", "Helvetica", "Arial", sans-serif;
  font-size: 1.6em;
  font-weight: 300;
  letter-spacing: 0.01em;
  line-height: 1.6;
}

*,
*:after,
*:before {
  box-sizing: inherit;
}

blockquote {
  border-left: 0.3rem solid #d1d1d1;
  margin-left: 0;
  margin-right: 0;
  padding: 1rem 1.5rem;
}
blockquote *:last-child {
  margin: 0;
}

.button,
button,
input[type='button'],
input[type='reset'],
input[type='submit'] {
  background-color: #9b4dca;
  border: 0.1rem solid #9b4dca;
  border-radius: 0.4rem;
  color: #fff;
  cursor: pointer;
  display: inline-block;
  font-size: 1.1rem;
  font-weight: 700;
  height: 3.8rem;
  letter-spacing: 0.1rem;
  line-height: 3.8rem;
  padding: 0 3rem;
  text-align: center;
  text-decoration: none;
  text-transform: uppercase;
  white-space: nowrap;
}
.button:hover, .button:focus,
button:hover,
button:focus,
input[type='button']:hover,
input[type='button']:focus,
input[type='reset']:hover,
input[type='reset']:focus,
input[type='submit']:hover,
input[type='submit']:focus {
  background-color: #606c76;
  border-color: #606c76;
  color: #fff;
  outline: 0;
}
.button.button-disabled, .button[disabled],
button.button-disabled,
button[disabled],
input[type='button'].button-disabled,
input[type='button'][disabled],
input[type='reset'].button-disabled,
input[type='reset'][disabled],
input[type='submit'].button-disabled,
input[type='submit'][disabled] {
  opacity: 0.5;
  cursor: default;
}
.button.button-disabled:hover, .button.button-disabled:focus, .button[disabled]:hover,...