Add avatars on accounts list

app/models/account.coffee

@@ -4,6 +4,7 @@
 Account = Model.extend
   name:         DS.attr()
   type:         DS.attr()
+  avatarUrl:    DS.attr()
   reposCount:   DS.attr('number')
   subscribed:   DS.attr('boolean')
   education:    DS.attr('boolean')

app/templates/profile/accounts.hbs

@@ -19,7 +19,7 @@
       {{#link-to "account" view.account class="name"}}
         <div class="media">
           <div class="media-elem">
-            <img src="//placehold.it/50x50" alt="">
+            <img {{bind-attr src="view.avatarUrl"}} alt="">
           </div>
           <div class="media-body">
             <h2>{{view.name}}</h2>

app/views/accounts-list.coffee

@@ -25,6 +25,10 @@ View = Ember.CollectionView.extend
       accountUrl(@get('account.login'))
     ).property('account.login')
 
+    avatarUrl: (->
+      @get('account.avatarUrl') || "//placehold.it/50x50"
+    ).property('account.avatarUrl')
+
     click: ->
       @get('controller').transitionToRoute("account", @get('account.login'))