Enable Rails 5 behavior for exceptions in after_commit callbacks

app/models/reshare.rb

@@ -18,7 +18,7 @@ class Reshare < Post
   end
 
   after_commit :on => :create do
-    self.root.update_reshares_counter
+    self.root.update_reshares_counter if self.root.present?
   end
 
   after_destroy do

config/application.rb

@@ -89,5 +89,8 @@ module Diaspora
       g.template_engine :haml
       g.test_framework  :rspec
     end
+
+    # Will be default with Rails 5
+    config.active_record.raise_in_transactional_callbacks = true
   end
 end