Show categories on the user streams for topics.

app/assets/javascripts/discourse/models/user_action.js

@@ -30,6 +30,13 @@ _.each(UserActionTypes, function (k, v) {
 
 Discourse.UserAction = Discourse.Model.extend({
 
+  _attachCategory: function() {
+    var categoryId = this.get('category_id');
+    if (categoryId) {
+      this.set('category', Discourse.Category.findById(categoryId));
+    }
+  }.on('init'),
+
   /**
     Return an i18n key we will use for the description text of a user action.
 

app/assets/javascripts/discourse/templates/user/stream.js.handlebars

@@ -5,6 +5,7 @@
       <span class='time'>{{unboundDate path="created_at" leaveAgo="true"}}</span>
       <span class="title">
         <a href="{{unbound postUrl}}">{{unbound title}}</a>
+        {{categoryLink category}}
       </span>
       <span class="type">{{unbound descriptionHtml}}</span>
     </div>