added envs for cert so that we can set prod path for prod certs

src/config/app.ts

@@ -7,6 +7,8 @@ module.exports = {
   hostname: process.env.HOSTNAME || 'ysbraid.localhost',
   environment: process.env.ENVIRONMENT || 'development',
   log_level: process.env.LOG_LEVEL || 'debug',
+  privateKey: process.env.PRIVATE_KEY || 'certs/key.pem',
+  certificate: process.env.CERTIFICATE || 'certs/cert.pem',
   signOptions : {
     issuer:  'Yardstick Software',
     subject:  'Braid JWT',