Fix /p/post/user route not saving referrals

Make user id optional for /p/id/uid
Add /posts/id/raw route for debugging failed post processing

spec/controllers/posts_controller_spec.rb

@@ -49,10 +49,11 @@ describe PostsController do
 
   describe 'short_link' do
     let(:post) { Fabricate(:post) }
+    let(:user) { Fabricate(:user) }
 
     it 'logs the incoming link once' do
       IncomingLink.expects(:add).once.returns(true)
-      get :short_link, post_id: post.id, user_id: 999
+      get :short_link, post_id: post.id, user_id: user.id
       response.should be_redirect
     end
   end