Fix extra fields

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    timeline (0.1.1)
+    timeline (0.1.4)
       activemodel (~> 3.2)
       activesupport (~> 3.2)
       hashie

lib/timeline/track.rb

@@ -63,10 +63,12 @@ def add_activity_to_followers(activity_item, followers)
     end
 
     def add_extra_fields(extra_fields)
-      if extra_fields.any?
-        extra_fields.inject({}) do |sum, value|
-          sum[value.to_sym] = send value.to_sym
+      if !extra_fields.nil? and extra_fields.any?
+        extras = {}
+        extra_fields.each do |value|
+          extras[value] = send(value)
         end
+        extras
       else
         {}
       end

spec/track_spec.rb

@@ -30,6 +30,42 @@ def to_s
   end
 end
 
+class Comment
+  extend ActiveModel::Callbacks
+
+  define_model_callbacks :create
+  attr_accessor :id, :creator_id
+
+  include Timeline::Track
+
+  track :new_comment, extra_fields: [:post_name, :post_id]
+
+  def initialize(options={})
+    @creator_id = options.delete :creator_id
+  end
+
+  def save
+    run_callbacks :create
+    true
+  end
+
+  def post_id
+    1
+  end
+
+  def post_name
+    "My Post"
+  end
+
+  def creator
+    User.find(creator_id)
+  end
+
+  def to_s
+    "Comment"
+  end
+end
+
 class User
   include Timeline::Actor
   attr_accessor :id, :to_param
@@ -78,4 +114,13 @@ def find user_id
       follower.timeline.last.actor.id.should == 1
     end
   end
+
+  describe "with extra_fields" do
+    let(:comment) { Comment.new(creator_id: creator.id, id: 1) }
+
+    it "stores the extra fields in the timeline" do
+      comment.save
+      creator.timeline.first.should respond_to :post_id
+    end
+  end
 end