Earlier it was working fine. I have been playing little bit config. So may be i have changed some config unknowingly.
here is config of environment/development.rb
reload! only reloads the latest code in the console environment. It does not re-initialize existing objects.
This means if you have already instantiated any objects, their attributes would not be updated - including newly introduced validations. However, if you create a new object, its attributes (and also validations) will reflect the reloaded code. more here