I have 2 divs in the sidebar and the second one (with class "bottom") should be sticky to the bottom of the div, how can I do that? This is the code:

```
<div class="header"></div>
<div class="container">
  <div class="sidebar">
    <div class="top">topcontent</div>
    <div class="bottom">bottomcontent</div>
  </div>
  <div class="main"></div>
</div>
<div class="footer"></div> 

```