fix: use app.js instead of index.js
add koa as dependency
disable strict mode

/app/node_modules/koa/node_modules/koa-compose/index.js:108
console.log('  \033[90mbody\033[0m: %j', ctx.body);
SyntaxError: Octal literals are not allowed in strict mode.
use env var $PORT
use env var process.env.PORT