Can you confirm you followed the steps at https://docs.bitnami.com/google/apps/ghost/#how-to-upgrade-ghost?
As Ghost just bumped its major version, upgrading Ghost from v.0.11.9-0 to v.1.0.0 can be very problematic because the new version may have changed a lot how it process data. A simple upgrade process (as documented in Bitnami Documentation) may not fully work.
As they mention in the announce post:
Ghost 1.0.0 is a major upgrade, with breaking changes and no automatic migration path.
Ghost have put down a migration guide for Ghost 1.0.0 and it basically implies backing up your data and restore it in a new Ghost 1.0.0 instance:
We are working on packaging and releasing the new version of Ghost so you can use it as soon as possible.
We will let you know here when the new version is available.
Just want to mention that Ghost 0.11.x is will be under Long Term Support for 6 months.