message: add forum, slackin links to footer
diff: <div class="container">
  <hr/>
  <div class="row">
  - <div class="col s4 foot-left"><a routerLink="/about" routerLinkActive="active" id ="about"><span>About Us</span></a></div>
  + <div class="col s4 foot-left">
  + <ul>
  + <a routerLink="/about" routerLinkActive="active" id ="about"><span>About Us</span></a>
  + <a target="_blank" href="http://forum.code4socialgood.org/"><span>Forum</span></a>
  + <a target="_blank" href="http://join-our-slack.code4socialgood.org/"><span>Chat</span></a>
  + </ul>
  + </div>
  <div class="col offset-s4 s4 foot-right">
  <ul>
  <li><a href="mailto:info@code4socialgood.org" class="mdi mdi-email mdi-24px"></a></li>
  