application.css.scss

// Sticky Footer CSS
// http://www.cssstickyfooter.com/

$sticky-footer-height: 80px;  // must be same height as the footer

* {
  margin: 0;
  padding: 0;
} 

html,
body {
  height: 100%;
}

#sticky-wrapper {
  min-height: 100%;
}

#sticky-main {
  overflow: auto;
  padding-bottom: $sticky-footer-height;
}

footer {
  border: none;
  clear: both;
  height: $sticky-footer-height;
  margin-top: -$sticky-footer-height;
  padding: 0px;
  position: relative;
} 

body:before {  // Opera Fix
  content: "";
  float: left;
  height: 100%;
  margin-top: -32767px;
  width: 0;
}

application.html.haml

!!!
%html
  %head
  %body
    #sticky-wrapper
      #sticky-main
        .container
    %footer
      .container