編集:トール 0.17.0 にロールバックしたところ、うまくいったようです。理由はわかりませんが、あります。
原因はわかりましたが、自動テストでテストの実行が停止し、次のエラーが発生しました。
"/usr/local/rvm/rubies/ruby-1.9.3-p194/bin/ruby" -rrubygems -S "/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rspec-core-2.13.1/exe/rspec" --tty "/Users/charliekim/programming/Ganesh/spec/controllers/pages_controller_spec.rb" "/Users/charliekim/programming/Ganesh/spec/controllers/student_groups_controller_spec.rb" "/Users/charliekim/programming/Ganesh/spec/controllers/students_controller_spec.rb" "/Users/charliekim/programming/Ganesh/spec/controllers/users_controller_spec.rb" "/Users/charliekim/programming/Ganesh/spec/models/student_group_spec.rb" "/Users/charliekim/programming/Ganesh/spec/models/student_spec.rb" "/Users/charliekim/programming/Ganesh/spec/models/user_spec.rb" "/Users/charliekim/programming/Ganesh/spec/requests/layout_links_spec.rb"
/usr/local/rvm/gems/ruby-1.9.3-p194@global/gems/bundler-1.3.4/lib/bundler/spec_set.rb:92:in `block in materialize': Could not find thor-0.18.0 in any of the sources (Bundler::GemNotFound)
from /usr/local/rvm/gems/ruby-1.9.3-p194@global/gems/bundler-1.3.4/lib/bundler/spec_set.rb:85:in `map!'
from /usr/local/rvm/gems/ruby-1.9.3-p194@global/gems/bundler-1.3.4/lib/bundler/spec_set.rb:85:in `materialize'
from /usr/local/rvm/gems/ruby-1.9.3-p194@global/gems/bundler-1.3.4/lib/bundler/definition.rb:114:in `specs'
from /usr/local/rvm/gems/ruby-1.9.3-p194@global/gems/bundler-1.3.4/lib/bundler/definition.rb:159:in `specs_for'
from /usr/local/rvm/gems/ruby-1.9.3-p194@global/gems/bundler-1.3.4/lib/bundler/definition.rb:148:in `requested_specs'
from /usr/local/rvm/gems/ruby-1.9.3-p194@global/gems/bundler-1.3.4/lib/bundler/environment.rb:18:in `requested_specs'
from /usr/local/rvm/gems/ruby-1.9.3-p194@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:13:in `setup'
from /usr/local/rvm/gems/ruby-1.9.3-p194@global/gems/bundler-1.3.4/lib/bundler.rb:120:in `setup'
from /usr/local/rvm/gems/ruby-1.9.3-p194@global/gems/bundler-1.3.4/lib/bundler/setup.rb:17:in `<top (required)>'
from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:60:in `require'
from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:60:in `rescue in require'
from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:35:in `require'
from /Users/charliekim/programming/Ganesh/config/boot.rb:6:in `<top (required)>'
from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from /Users/charliekim/programming/Ganesh/config/application.rb:1:in `<top (required)>'
from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from /Users/charliekim/programming/Ganesh/config/environment.rb:2:in `<top (required)>'
from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from /Users/charliekim/programming/Ganesh/spec/spec_helper.rb:3:in `<top (required)>'
from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from /Users/charliekim/programming/Ganesh/spec/controllers/pages_controller_spec.rb:1:in `<top (required)>'
from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/rspec-core-2.13.1/lib/rspec/core/configuration.rb:819:in `load'
from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/rspec-core-2.13.1/lib/rspec/core/configuration.rb:819:in `block in load_spec_files'
from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/rspec-core-2.13.1/lib/rspec/core/configuration.rb:819:in `each'
from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/rspec-core-2.13.1/lib/rspec/core/configuration.rb:819:in `load_spec_files'
from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/rspec-core-2.13.1/lib/rspec/core/command_line.rb:22:in `run'
from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/rspec-core-2.13.1/lib/rspec/core/runner.rb:80:in `run'
from /usr/local/rvm/gems/ruby-1.9.3-p194/gems/rspec-core-2.13.1/lib/rspec/core/runner.rb:17:in `block in autorun'
SO で GemNotFound エラーに関する同様の問題をいくつか見たことがありますが、解決策はこれに対してうまくいかないようです。bundle exex gem list
Thor 0.18.0 を実行すると存在します。