ruby on rails DEPRECATION WARNING: Giving :session_key to SessionStore is deprecated, please use :key instead.

DEPRECATION WARNING: Giving :session_key to SessionStore is deprecated, please use :key instead. (called from new at /usr/lib/ruby/gems/1.8/gems/actionpack-2.3.8/lib/action_controller/middleware_stack.rb:72)

=== please go to config/environment.rb

config.action_controller.session = {
    :session_key => '_blog_session',
    :secret      => 'f3f57b71ef9345ffccd0c4e841d8e74bb2e7d2ef692a5303bb455fea0667a62d30458d17f95766b12906aa6c2a3c29d584a55dd18426ffc04610be49956a51af'
  }

change to:

config.action_controller.session = {
    :key => '_blog_session',
    :secret      => 'f3f57b71ef9345ffccd0c4e841d8e74bb2e7d2ef692a5303bb455fea0667a62d30458d17f95766b12906aa6c2a3c29d584a55dd18426ffc04610be49956a51af'
  }

thank..