add a deprecation banner

Author: jenweber

_layouts/default.html

@@ -46,6 +46,13 @@ <h1><a href="/"><img src="/assets/images/ember-cli-logo-small-dark.png" alt="Emb
                     <span class="glyphicon glyphicon-pencil"></span>
                   </a>
                   <h1>{{guide.title}}</h1>
+                  <div class="deprecation-banner row">
+                    The Ember CLI Guides have moved! Please visit
+                    <a href="https://cli.emberjs.com">
+                      cli.emberjs.com
+                    </a>
+                    instead for the most up-to-date content. 
+                  </div>
                   <p>{{guide.content}}</p>
                 </div>
                 {% endif %}

assets/main.scss

@@ -368,6 +368,14 @@ body {
 
 }
 
+.deprecation-banner.row {
+  margin-top: 15px;
+  margin-bottom: 15px;
+  font-size: 1.5em;
+  background-color: #ffefcc;
+  padding: 20px;
+}
+
 .highlight .lineno {
   display: none;
 }