errors in rails console

hi

when i enter rails console this errors displays ,could you help me please ?

/home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:252:in `require’: cannot load such file – readline (LoadError)

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:252:in `block in require'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:237:in `load_dependency'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:252:in `require'

from /home/farnaz/.rbenv/versions/2.1.5/lib/ruby/2.1.0/irb/completion.rb:9:in `<top (required)>'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:252:in `require'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:252:in `block in require'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:237:in `load_dependency'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:252:in `require'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/railties-4.2.0.beta4/lib/rails/commands/console.rb:3:in `<top (required)>'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:252:in `require'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:252:in `block in require'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:237:in `load_dependency'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:252:in `require'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/railties-4.2.0.beta4/lib/rails/commands/commands_tasks.rb:123:in `require_command!'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/railties-4.2.0.beta4/lib/rails/commands/commands_tasks.rb:58:in `console'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/railties-4.2.0.beta4/lib/rails/commands/commands_tasks.rb:39:in `run_command!'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/railties-4.2.0.beta4/lib/rails/commands.rb:17:in `<top (required)>'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:252:in `require'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:252:in `block in require'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:237:in `load_dependency'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:252:in `require'

from /home/farnaz/workspace/sample_app/bin/rails:8:in `<top (required)>'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:246:in `load'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:246:in `block in load'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:237:in `load_dependency'

from /home/farnaz/workspace/sample_app/path/ruby/2.1.0/gems/activesupport-4.2.0.beta4/lib/active_support/dependencies.rb:246:in `load'

from /home/farnaz/.rbenv/versions/2.1.5/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:54:in `require'

from /home/farnaz/.rbenv/versions/2.1.5/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:54:in `require'

from -e:1:in `<main>'

and this is my gem file :

gem ‘rails’, ‘4.2.0.beta4’

gem ‘bcrypt’, ‘3.1.7’

gem ‘faker’, ‘1.4.2’

gem ‘rake’

gem ‘carrierwave’, ‘0.10.0’

gem ‘mini_magick’, ‘3.8.0’

gem ‘fog’, ‘1.23.0’

gem ‘will_paginate’, ‘3.0.7’

gem ‘bootstrap-will_paginate’, ‘0.0.10’

gem ‘bootstrap-sass’, ‘3.2.0.0’

gem ‘sass-rails’, ‘5.0.0.beta1’

gem ‘uglifier’, ‘2.5.3’

gem ‘coffee-rails’, ‘4.0.1’

gem ‘jquery-rails’, ‘4.0.0.beta2’

gem ‘turbolinks’, ‘2.3.0’

gem ‘jbuilder’, ‘2.2.3’

gem ‘arel’, ‘6.0.0.beta2’

gem ‘sdoc’, ‘0.4.0’, group: :doc

group :development, :test do

gem ‘sqlite3’, ‘1.3.9’

gem ‘byebug’, ‘3.4.0’

gem ‘web-console’, ‘2.0.0.beta3’

gem ‘spring’, ‘1.1.3’

end

group :test do

gem ‘minitest-reporters’, ‘1.0.5’

gem ‘mini_backtrace’, ‘0.1.3’

gem ‘guard-minitest’, ‘2.3.1’

end

group :production do

gem ‘pg’, ‘0.17.1’

gem ‘rails_12factor’, ‘0.0.2’

gem ‘unicorn’, ‘4.8.3’

end

http://stackoverflow.com/questions/9340497/cannot-load-such-file-readline-loaderror-when-running-heroku-create-stack