Error installing Rails using rbenv

I use rbenv for installing Ruby-on-rails,i used gem install rails command, it seems it installs many dependencies without any problem but suddenly this error pops out:

ERROR: Error installing rails: invalid gem: package is corrupt, exception while verifying: undefined method `size' for nil:NilClass (NoMethodError) in /Users/pouyankhodabakhsh/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/cache/loofah-2.0.3.gem

I could not find anything useful to deal with the error and have no idea why this is happening.Have somebody else got any similar errors? How did you fix it and how could i do so?

I already installed Ruby 2.2.3 using ruby-build.I use a mac with El Capitan, Also i have the same problem trying to install bundler but i didn't have any errors during the installation of nokogiri.