Make User#accessible_deploy_keys works in rails4

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/models/user.rb

@@ -373,7 +373,7 @@ class User < ActiveRecord::Base
   end
 
   def accessible_deploy_keys
-    DeployKey.in_projects(self.authorized_projects).uniq
+    DeployKey.in_projects(self.authorized_projects.pluck(:id)).uniq
   end
 
   def created_by