Redmine

I am installing Redmine on Ubuntu 14.04.
But I am blocked at step 6 - Database schema objects creation.
(https://www.redmine.org/projects/redmine/wiki/RedmineInstall)
How to fix it? Thank you!

root@xyz:/var/www/html/redmine# RAILS_ENV=production bundle exec rake db:migrate
rake aborted!
ActiveRecord::StatementInvalid: Mysql2::Error: Table 'schema_migrations' already exists: CREATE TABLE `schema_migrations` (`version` varchar(255) NOT NULL) ENGINE=InnoDB
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:305:in `query'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:305:in `block in execute'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract_adapter.rb:473:in `block in log'
/var/lib/gems/1.9.1/gems/activesupport-4.2.4/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract_adapter.rb:467:in `log'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:305:in `execute'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/connection_adapters/mysql2_adapter.rb:231:in `execute'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract/schema_statements.rb:208:in `create_table'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:468:in `create_table'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/schema_migration.rb:29:in `create_table'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/connection_adapters/mysql2_adapter.rb:45:in `initialize_schema_migrations_table'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/migration.rb:922:in `initialize'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/migration.rb:820:in `new'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/migration.rb:820:in `up'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/migration.rb:798:in `migrate'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/tasks/database_tasks.rb:137:in `migrate'
/var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/railties/databases.rake:44:in `block (2 levels) in <top (required)>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)