Add link to Arlington Retrocession info

Author: kalimar

css/app.css

@@ -37,6 +37,10 @@ <h2>Links</h2>
             <h1>Upcoming Events</h1>
           </header>
           <section class="main-content">
+            <div class="retrocession">
+              <h2>Ruby Retrocession: March 5, 2016</h2>
+              You can now register for Retrocession! A day-long unconference where the topics and discussions are all determined day-of by the attendees. Ruby not required. Learn more about the event <a href="http://www.meetup.com/Arlington-Ruby/messages/78036354/">here</a>.
+            </div>
             <div id="arlington-meetup-card-collection" data-component="meetup-card-collection" data-meetup-card-max-return="3" data-meetup-card-url="http://api.meetup.com/2/events/?key=6468958671031515c1e1e284e4413&group_id=1815773&status=upcoming&order=time&limited_events=false&desc=false&callback=JSON_CALLBACK&offset=0&format=json&page=200&fields="></div>
           </section>
         </article>