我正在尝试从用户的完整个人资料中获取信息，特别是所有过去的职位。
以下是devise.rb中的代码：
config.omniauth :linkedin, ENV["LINKEDIN_API_KEY"], ENV["LINKEDIN_SECRET_KEY"],
:scope => 'r_fullprofile r_emailaddress r_network',
:fields => %w(id email-address first-name last-name headline industry picture-url public-profile-url location connections three-current-positions three-past-positions recommendations-received honors-awards interests patents publications job-bookmarks)
我仍然只获得基本信息，如何获取过去的职位和其他完整的个人资料信息？
这些是我宝石文件中与auth相关的宝石：
gem "linkedin"
gem "omniauth"
gem "omniauth-linkedin"
gem "omniauth-facebook"
gem "devise"
我正在使用Rails4