Configure LinkedIn Omniauth

client = get_client
positions = client.profile(:fields => ["positions"])
positions.values # should return a hash with companies, dates and so on.

# This is what I did with Devise:
# devise.rb
  config.omniauth :linkedin, ENV['OAUTH_LINKEDIN_ID'], ENV['OAUTH_LINKEDIN_SECRET'],
    fields: %w(id email-address first-name last-name headline industry picture-url public-profile-url location num-connections positions)
    
    
# omniauth_callbacks_controller.rb
    def self.provides_callback_for(provider)
    class_eval %Q{
      def #{provider}
        @user = User.find_for_oauth(env["omniauth.auth"], current_user)

        if @user.persisted?
          handle_redirect("devise.#{provider}_uid", "#{provider}".capitalize)
        else
          session["devise.#{provider}_data"] = env["omniauth.auth"]
          redirect_to new_user_registration_url
        end
      end
    }
  end

  [:facebook, :google_oauth2, :linkedin, :twitter].each do |provider|
    provides_callback_for provider
  end

  def handle_redirect(_session_variable, kind)
    # here we force the locale to the session locale so it siwtches to the correct locale
    I18n.locale = session[:omniauth_login_locale] || I18n.default_locale
    sign_in_and_redirect @user, event: :authentication
    set_flash_message(:notice, :success, kind: kind) if is_navigational_format?
  end
  
# user.rb
devise :omniauthable, :omniauth_providers => [:facebook, :google_oauth2, :linkedin, :twitter]
def self.find_for_oauth(auth, signed_in_resource = nil)
  ...
  profile.positions = oauth.extra.raw_info.positions
  ...
end