omniauth.rb

module OmniAuth::Strategies  
    class Foo < Shibboleth
        def name 
          :foo
        end 
    end

    class Bar < Shibboleth
        def name 
          :bar
        end 
    end
end

Rails.application.config.middleware.use OmniAuth::Builder do

  provider :foo, { 
    :shib_session_id_field     => "Shib-Session-ID",
    :shib_application_id_field => "Shib-Application-ID",
    :debug                     => false
  }

  provider :bar, {
    :shib_session_id_field     => "Shib-Session-ID",
    :shib_application_id_field => "Shib-Application-ID",
    :debug                     => false
  }
end