Rails 4 application is throwing the errors during the startup with development. I use mongodb for DB.
flex/config/environments/development.rb:1:in `<top (required)>': undefined method `configure' for #<Flex::Application:0x007f49ec793870> (NoMethodError)
Ruby version ruby 2.0.0dev (2013-02-08 trunk 39161)
pls help on this