我试图捆绑以下宝石：
gem 'binding_of_caller', '~> 0.7.2'
这会导致以下错误消息。我已经环顾四周看看如何解决它，但找不到任何有用的东西。
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/tmpdir.rb:85:in `mkdir': ERROR: Failed to build gem native extension. (Gem::Ext::BuildError)
Permission denied - ./.gem.20140529-2393-154cu0
Gem files will remain installed in /Library/Ruby/Gems/2.0.0/gems/binding_of_caller-0.7.2 for inspection.
Results logged to /Library/Ruby/Gems/2.0.0/extensions/universal-darwin-13/2.0.0/binding_of_caller-0.7.2/gem_make.out
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/tmpdir.rb:85:in `block in mktmpdir'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/tmpdir.rb:142:in `create'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/tmpdir.rb:85:in `mktmpdir'
from /Library/Ruby/Site/2.0.0/rubygems/ext/ext_conf_builder.rb:14:in `build'
from /Library/Ruby/Site/2.0.0/rubygems/ext/builder.rb:161:in `block (2 levels) in build_extension'
from /Library/Ruby/Site/2.0.0/rubygems/ext/builder.rb:160:in `chdir'
from /Library/Ruby/Site/2.0.0/rubygems/ext/builder.rb:160:in `block in build_extension'
from /Library/Ruby/Site/2.0.0/rubygems/ext/builder.rb:159:in `synchronize'
from /Library/Ruby/Site/2.0.0/rubygems/ext/builder.rb:159:in `build_extension'
from /Library/Ruby/Site/2.0.0/rubygems/ext/builder.rb:198:in `block in build_extensions'
from /Library/Ruby/Site/2.0.0/rubygems/ext/builder.rb:195:in `each'
from /Library/Ruby/Site/2.0.0/rubygems/ext/builder.rb:195:in `build_extensions'
from /Library/Ruby/Site/2.0.0/rubygems/specification.rb:1436:in `block in build_extensions'
from /Library/Ruby/Site/2.0.0/rubygems/user_interaction.rb:45:in `use_ui'
from /Library/Ruby/Site/2.0.0/rubygems/specification.rb:1434:in `build_extensions'
from /Library/Ruby/Site/2.0.0/rubygems/stub_specification.rb:60:in `build_extensions'
from /Library/Ruby/Site/2.0.0/rubygems/basic_specification.rb:56:in `contains_requirable_file?'
from /Library/Ruby/Site/2.0.0/rubygems/specification.rb:925:in `block in find_inactive_by_path'
from /Library/Ruby/Site/2.0.0/rubygems/specification.rb:924:in `each'
from /Library/Ruby/Site/2.0.0/rubygems/specification.rb:924:in `find'
from /Library/Ruby/Site/2.0.0/rubygems/specification.rb:924:in `find_inactive_by_path'
from /Library/Ruby/Site/2.0.0/rubygems.rb:185:in `try_activate'
from /Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:132:in `rescue in require'
from /Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:144:in `require'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.6.0.rc2/lib/bundler/vendor/net/http/persistent.rb:12:in `<top (required)>'
from /Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.6.0.rc2/lib/bundler/vendored_persistent.rb:3:in `<top (required)>'
from /Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.6.0.rc2/lib/bundler/fetcher.rb:1:in `<top (required)>'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.6.0.rc2/lib/bundler/cli/install.rb:68:in `run'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.6.0.rc2/lib/bundler/cli.rb:146:in `install'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.6.0.rc2/lib/bundler/vendor/thor/command.rb:27:in `run'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.6.0.rc2/lib/bundler/vendor/thor/invocation.rb:121:in `invoke_command'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.6.0.rc2/lib/bundler/vendor/thor.rb:363:in `dispatch'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.6.0.rc2/lib/bundler/vendor/thor/base.rb:440:in `start'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.6.0.rc2/lib/bundler/cli.rb:9:in `start'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.6.0.rc2/bin/bundle:20:in `block in <top (required)>'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.6.0.rc2/lib/bundler/friendly_errors.rb:5:in `with_friendly_errors'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.6.0.rc2/bin/bundle:20:in `<top (required)>'
from /usr/bin/bundle:23:in `load'
from /usr/bin/bundle:23:in `<main>'
我不知道如何解决这个问题。我已经尝试了bundle update但是没有用。
有人可以帮忙吗？
由于