def authenticate user, password
      Oath.config.authentication_service.new(user, password).perform
    end
def authenticate user, password
      Oath.config.authentication_service.new(user, password).perform
    end
Authenticates a user given a password

 @note Uses the {Oath::Services::Authentication} service to verify the user's credentials

 @param user [User] the user
 @param password [String] the password
 @return [User] if authentication succeeded
 @return [nil] if authentication failed