Bundler could not find compatible versions for gem "nokogiri"

I push a rails app to appfog, but got following error message: /var/vcap.local/dea/apps/superb-0-dc92a2e492e46c40c06d2abc3ad59841/app/rubygems ruby/1.9.1/gems/bundler-1.1.3/lib/bundler/resolver.rb:129:in `block in resolve' Bundler could not find compatible versions for gem "nokogiri": (Bundler::Versi nConflict) In snapshot (Gemfile.lock): nokogiri (1.5.6) In Gemfile: capybara (= 1.1.2) ruby depends on nokogiri (>= 1.3.3) ruby Running `bundle update` will rebuild your snapshot from scratch, using only the gems in your Gemfile, which may resolve the conflict. and my Gemfile: ``` source 'https://rubygems.org' gem 'rails', '3.2.12' gem 'mysql2' gem 'pg' gem 'thin' gem 'sqlite3' group :development, :test do gem 'rspec-rails', '2.11.0' end # Gems used only for assets and not required # in production environments by default. group :assets do gem 'sass-rails', '3.2.5' gem 'coffee-rails', '3.2.2' gem 'uglifier', '1.2.3' end gem 'jquery-rails', '2.0.2' group :test do gem 'capybara', '1.1.2' end ``` How to resolve the problem? edit： add Gemfile.lock ``` GEM remote: https://rubygems.org/ specs: actionmailer (3.2.12) actionpack (= 3.2.12) mail (~> 2.4.4) actionpack (3.2.12) activemodel (= 3.2.12) activesupport (= 3.2.12) builder (~> 3.0.0) erubis (~> 2.7.0) journey (~> 1.0.4) rack (~> 1.4.5) rack-cache (~> 1.2) rack-test (~> 0.6.1) sprockets (~> 2.2.1) activemodel (3.2.12) activesupport (= 3.2.12) builder (~> 3.0.0) activerecord (3.2.12) activemodel (= 3.2.12) activesupport (= 3.2.12) arel (~> 3.0.2) tzinfo (~> 0.3.29) activeresource (3.2.12) activemodel (= 3.2.12) activesupport (= 3.2.12) activesupport (3.2.12) i18n (~> 0.6) multi_json (~> 1.0) arel (3.0.2) builder (3.0.4) capybara (1.1.2) mime-types (>= 1.16) nokogiri (>= 1.3.3) rack (>= 1.0.0) rack-test (>= 0.5.4) selenium-webdriver (~> 2.0) xpath (~> 0.1.4) childprocess (0.3.8) ffi (~> 1.0, >= 1.0.11) coffee-rails (3.2.2) coffee-script (>= 2.2.0) railties (~> 3.2.0) coffee-script (2.2.0) coffee-script-source execjs coffee-script-source (1.5.0) daemons (1.1.9) diff-lcs (1.1.3) erubis (2.7.0) eventmachine (1.0.1-x86-mingw32) execjs (1.4.0) multi_json (~> 1.0) ffi (1.4.0-x86-mingw32) hike (1.2.1) i18n (0.6.4) journey (1.0.4) jquery-rails (2.0.2) railties (>= 3.2.0, < 5.0) thor (~> 0.14) json (1.7.7) mail (2.4.4) i18n (>= 0.4.0) mime-types (~> 1.16) treetop (~> 1.4.8) mime-types (1.21) multi_json (1.6.1) mysql2 (0.3.11-x86-mingw32) nokogiri (1.5.6-x86-mingw32) pg (0.14.1-x86-mingw32) polyglot (0.3.3) rack (1.4.5) rack-cache (1.2) rack (>= 0.4) rack-ssl (1.3.3) rack rack-test (0.6.2) rack (>= 1.0) rails (3.2.12) actionmailer (= 3.2.12) actionpack (= 3.2.12) activerecord (= 3.2.12) activeresource (= 3.2.12) activesupport (= 3.2.12) bundler (~> 1.0) railties (= 3.2.12) railties (3.2.12) actionpack (= 3.2.12) activesupport (= 3.2.12) rack-ssl (~> 1.3.2) rake (>= 0.8.7) rdoc (~> 3.4) thor (>= 0.14.6, < 2.0) rake (10.0.3) rdoc (3.12.2) json (~> 1.4) rspec (2.11.0) rspec-core (~> 2.11.0) rspec-expectations (~> 2.11.0) rspec-mocks (~> 2.11.0) rspec-core (2.11.1) rspec-expectations (2.11.3) diff-lcs (~> 1.1.3) rspec-mocks (2.11.3) rspec-rails (2.11.0) actionpack (>= 3.0) activesupport (>= 3.0) railties (>= 3.0) rspec (~> 2.11.0) rubyzip (0.9.9) sass (3.2.6) sass-rails (3.2.5) railties (~> 3.2.0) sass (>= 3.1.10) tilt (~> 1.3) selenium-webdriver (2.30.0) childprocess (>= 0.2.5) multi_json (~> 1.0) rubyzip websocket (~> 1.0.4) sprockets (2.2.2) hike (~> 1.2) multi_json (~> 1.0) rack (~> 1.0) tilt (~> 1.1, != 1.3.0) sqlite3 (1.3.7-x86-mingw32) thin (1.5.0) daemons (>= 1.0.9) eventmachine (>= 0.12.6) rack (>= 1.0.0) thor (0.17.0) tilt (1.3.3) treetop (1.4.12) polyglot polyglot (>= 0.3.1) tzinfo (0.3.35) uglifier (1.2.3) execjs (>= 0.3.0) multi_json (>= 1.0.2) websocket (1.0.7) xpath (0.1.4) nokogiri (~> 1.3) PLATFORMS x86-mingw32 DEPENDENCIES capybara (= 1.1.2) coffee-rails (= 3.2.2) jquery-rails (= 2.0.2) mysql2 pg rails (= 3.2.12) rspec-rails (= 2.11.0) sass-rails (= 3.2.5) sqlite3 thin uglifier (= 1.2.3) ```