OAuth gem workaround on JRuby

oauth-monkey-patch.rb

module OAuth::Signature::HMAC
  class Base < OAuth::Signature::Base
  private
    def digest
      self.class.digest_class Object.module_eval("::Digest::#{self.class.digest_klass}")
     digest  = OpenSSL::Digest::Digest.new('sha1')
     OpenSSL::HMAC.digest(digest, secret, signature_base_string)
    end
  end
end