def validate_certificates
      validate_each :certificates do |c|
        cert = self.grid.certificates.find_by(subject: c[:subject])
        unless cert
          [:not_found, "Certificate #{c[:subject]} does not exist"]
        else
          nil
        end
      end
    end
def validate_certificates
      validate_each :certificates do |c|
        cert = self.grid.certificates.find_by(subject: c[:subject])
        unless cert
          [:not_found, "Certificate #{c[:subject]} does not exist"]
        else
          nil
        end
      end
    end
Validates that the defined certificates exist