def register(token, email, granted_to_email, access_count, expire)
      save_config(token, {email: email, granted_to_email: granted_to_email, access_count: access_count})
      @redis.expire(token, expire)

      token
    end
def register(token, email, granted_to_email, access_count, expire)
      save_config(token, {email: email, granted_to_email: granted_to_email, access_count: access_count})
      @redis.expire(token, expire)

      token
    end
register one time token for given user in redis
 the generated token will have a field "email" in order to identify the associated user later