modify: bunle install error on travis

/home/travis/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/number_helper.rb:3:in `<module:NumberHelper>': uninitialized constant ActiveSupport::Autoload (NameError)
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/number_helper.rb:2:in `<module:ActiveSupport>'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/number_helper.rb:1:in `<top (required)>'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/core_ext/numeric/conversions.rb:2:in `require'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/core_ext/numeric/conversions.rb:2:in `<top (required)>'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/core_ext/numeric.rb:3:in `require'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/core_ext/numeric.rb:3:in `<top (required)>'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/core_ext.rb:2:in `require'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/core_ext.rb:2:in `block in <top (required)>'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/core_ext.rb:1:in `each'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/core_ext.rb:1:in `<top (required)>'
  from /home/travis/build/sue445/rubicure/lib/rubicure.rb:1:in `require'
  from /home/travis/build/sue445/rubicure/lib/rubicure.rb:1:in `<top (required)>'
  from /home/travis/build/sue445/rubicure/spec/spec_helper.rb:8:in `require'
  from /home/travis/build/sue445/rubicure/spec/spec_helper.rb:8:in `<top (required)>'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/rspec-core-3.0.0/lib/rspec/core/configuration.rb:1018:in `require'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/rspec-core-3.0.0/lib/rspec/core/configuration.rb:1018:in `block in requires='
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/rspec-core-3.0.0/lib/rspec/core/configuration.rb:1018:in `each'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/rspec-core-3.0.0/lib/rspec/core/configuration.rb:1018:in `requires='
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/rspec-core-3.0.0/lib/rspec/core/configuration_options.rb:101:in `block in process_options_into'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/rspec-core-3.0.0/lib/rspec/core/configuration_options.rb:100:in `each'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/rspec-core-3.0.0/lib/rspec/core/configuration_options.rb:100:in `process_options_into'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/rspec-core-3.0.0/lib/rspec/core/configuration_options.rb:22:in `configure'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/rspec-core-3.0.0/lib/rspec/core/runner.rb:96:in `setup'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/rspec-core-3.0.0/lib/rspec/core/runner.rb:85:in `run'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/rspec-core-3.0.0/lib/rspec/core/runner.rb:70:in `run'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/rspec-core-3.0.0/lib/rspec/core/runner.rb:38:in `invoke'
  from /home/travis/.rvm/gems/ruby-2.1.2/gems/rspec-core-3.0.0/exe/rspec:4:in `<top (required)>'
  from /home/travis/.rvm/gems/ruby-2.1.2/bin/rspec:23:in `load'
  from /home/travis/.rvm/gems/ruby-2.1.2/bin/rspec:23:in `<main>'