Gracefully handle exit

[nahtnam]

async function closeGracefully(signal) {
   console.log(`*^!@4=> Received signal to terminate: ${signal}`)
 
   await fastify.close()
   // await db.close() if we have a db connection in this app
   // await other things we should cleanup nicely
   process.exit()
}
process.on('SIGINT', closeGracefully)
process.on('SIGTERM', closeGracefully)

pulled from https://snyk.io/blog/10-best-practices-to-containerize-nodejs-web-applications-with-docker/