Reconnection in PostgreSQLAdapter

Based on these links

https://github.com/rails/rails/pull/6654#issuecomment-7684067
https://github.com/rails/rails/pull/7632

It looks like it has been fixed in master (Rails 4.0) and back-ported to 3.2 1 month ago so I assume it should be available in the next 3.2 release.