Cannot generate controller ,model or start rails server -

i started getting problems in generating controllers,models , starting rails server in new projects. able these things in old projects.

what can done resolve error?

os: ubuntu 15.04 ,ruby:2.1 ,rails: 4.2.0

error output:

aditya@aditya-pc:~/testrails/blog$ rails g controller  pages  warning: running `gem pristine --all` regenerate installed gemspecs (and deleting reinstalling bundle if use bundle --path) improve startup performance of spring. /var/lib/gems/2.1.0/gems/railties-4.2.0/lib/rails/railtie/configuration.rb:95:in `method_missing': undefined method `active_record' #<rails::application::configuration:0x00000002ec6c40> (nomethoderror)     /home/aditya/testrails/blog/config/application.rb:24:in `<class:application>'     /home/aditya/testrails/blog/config/application.rb:10:in `<module:blog>'     /home/aditya/testrails/blog/config/application.rb:9:in `<top (required)>'     /var/lib/gems/2.1.0/gems/spring-1.3.6/lib/spring/application.rb:82:in `require'     /var/lib/gems/2.1.0/gems/spring-1.3.6/lib/spring/application.rb:82:in `preload'     /var/lib/gems/2.1.0/gems/spring-1.3.6/lib/spring/application.rb:143:in `serve'     /var/lib/gems/2.1.0/gems/spring-1.3.6/lib/spring/application.rb:131:in `block in run'     /var/lib/gems/2.1.0/gems/spring-1.3.6/lib/spring/application.rb:125:in `loop'     /var/lib/gems/2.1.0/gems/spring-1.3.6/lib/spring/application.rb:125:in `run'     /var/lib/gems/2.1.0/gems/spring-1.3.6/lib/spring/application/boot.rb:18:in `<top (required)>'     /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'     /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'     -e:1:in `<main>' 

edit: removed rails , again installed. no effect, still having error.

have tried run bundle install in application?