我尝试使用google_drive gem来读取/写入Google工作表。我在第一个配置步骤（Errno::EACCES: Permission denied @ rb_sysopen - /config.json）中收到错误。我使用的是rvm，ruby 2.2.4，rails 4.2.5.1，并且谷歌拥有客户端ID /密码。有什么想法吗？
Errno::EACCES: Permission denied @ rb_sysopen - /config.json
/Users/RoccoBasso/.rvm/rubies/ruby-2.2.4/lib/ruby/2.2.0/open-uri.rb:36:in `initialize'
/Users/RoccoBasso/.rvm/rubies/ruby-2.2.4/lib/ruby/2.2.0/open-uri.rb:36:in `open'
/Users/RoccoBasso/.rvm/rubies/ruby-2.2.4/lib/ruby/2.2.0/open-uri.rb:36:in `open'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/google_drive-1.0.1/lib/google_drive.rb:144:in `saved_session'
/Users/RoccoBasso/Dropbox/Cannonball/immense-wildwood-9339/lib/tasks/update_user_digest_preferences.rake:2:in `block in <top (required)>'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/task.rb:248:in `call'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/task.rb:248:in `block in execute'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/task.rb:243:in `each'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/task.rb:243:in `execute'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/task.rb:187:in `block in invoke_with_call_chain'
/Users/RoccoBasso/.rvm/rubies/ruby-2.2.4/lib/ruby/2.2.0/monitor.rb:211:in `mon_synchronize'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/task.rb:180:in `invoke_with_call_chain'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/task.rb:173:in `invoke'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/application.rb:150:in `invoke_task'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/application.rb:106:in `block (2 levels) in top_level'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/application.rb:106:in `each'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/application.rb:106:in `block in top_level'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/application.rb:115:in `run_with_threads'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/application.rb:100:in `top_level'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/application.rb:78:in `block in run'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/application.rb:176:in `standard_exception_handling'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/lib/rake/application.rb:75:in `run'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/gems/rake-11.1.2/bin/rake:33:in `<top (required)>'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/bin/rake:22:in `load'
/Users/RoccoBasso/.rvm/gems/ruby-2.2.4/bin/rake:22:in `<main>'
Tasks: TOP => update_users_digest_preferences