PGError: ERROR: permission denied for relation (when using Heroku)

I had the similar problem on my Redmine application:

PG::InsufficientPrivilege: ERROR:  permission denied for relation settings
: SELECT  "settings".* FROM "settings"  WHERE "settings"."name" = 'plugin_redmine_wktime' LIMIT 1

My steps were:

1. I made a backup of old Redmine application and database.
2. I deployed a new version of Redmine - it worked perfectly
3. I restored old Redmine as a development server and I got an error when I tried to access the main webpage.

The cause of my problem was just in wrong username in old Redmine's config/database.yml