Log api response time metrics and produce useful time series graphs from Day1

[pulkitsinghal]

If you configure nginx to log API response times then you can look over such logs and see if your API responds within 200ms. In the future if some code ends up affecting performance negatively and causes a slowdown, you'll be able to catch it easily because you added this feature early on.

NewRelic is a more sophisticated option, easier to integrate but might kill the charm of learning.