Redmine

Hello

I am using Redmine project management tool since 2 weeks. I want to add plugins to my application. When I execute the command to migrate the tables to database it is giving following error.
C:\Ruby\myprojectdir\redmine-0.8.1>rake db:migrate_plugins --trace
(in C:/Ruby/myprojectdir/redmine-0.8.1)

• Invoke db:migrate_plugins (first_time)
• Invoke environment (first_time)
• Execute environment
• Execute db:migrate_plugins
  Migrating engines...
  rake aborted!
  #42000Unknown database 'redmine_development'
  i am using production database for my application.

Please help me how to set the database environment variable to production.

Thanks and regards