ruby - Cannot create application with rails -

i installed rails. while creating new application command:

rails new myapp 

the following error messages occur:

fetching gem metadata https://rubygems.org/.......... fetching gem metadata https://rubygems.org/.. resolving dependencies... installing rake (10.1.0)  errno::eacces: permission denied - /usr/local/lib/ruby/gems/2.0.0/build_info/rake-10.1.0.info error occurred while installing rake (10.1.0), , bundler cannot continue. make sure `gem install rake -v '10.1.0'` succeeds before bundling. 

the version of gem 4.0.0.

this seems permission problem change permission of directory , try:

gem install rake -v '10.1.0' 

and post logs if error happens.

or try:

sudo gem install rake -v '10.1.0' 

and post logs if there error again.