Solution 1 (css solution)
If you want to achieve this, just replace your footer css with this:
footer {
position: fixed;
bottom: 0;
right: 10px;
left: 10px;
height: 60px;
background-color: transparent;
color:black;
border: 1px dotted red;
}
Solution 2 (javascript solution)
If you want to achieve this just:
Load jQuery and add this into the javascript:
$('footer').width($('.jumbotron').width())
and change the footer position from absolute to fixed:
.footer {
position: fixed;
}