Cannot change CloudForms admin user password

Issue

• Unable to change admin user's password by following this KCS

[root@cf vmdb]# rails r "User.find_by_userid('admin').update_attributes(:password => 'newpwd')"

DEPRECATION WARNING: `config.serve_static_files` is deprecated and will be removed in Rails 5.1.
Please use `config.public_file_server.enabled = false` instead.
 (called from block in <top (required)> at /var/www/miq/vmdb/config/environments/production.rb:15)
/opt/rh/cfme-gemset/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/postgresql_adapter.rb:598:in `async_exec': PG::DiskFull: ERROR:  could not access status of transaction 0 (ActiveRecord::StatementInvalid)
DETAIL:  Could not write to file "pg_subtrans/116F" at offset 114688: No space left on device.