Fix layout of docker blog post summary

_sass/common/_article.scss

@@ -85,6 +85,7 @@ article {
         /* Setting a flex display to allow the proper border rendering
          * if placed next to a floating element. */
         display:        flex;
+        flex-direction: column;
         color:          $color-helmoltz-gray;
         border-left:    2px solid $color-content-light-gray;
         padding-left:   0.5rem;