Ridiculously slow first boot

Hello everybody.

So I built that website that was planned to be as git configuration tool :sweat::cold_sweat::clap::clap:

I used ember-cli-rails. But, I found FastBoot and I separated my website into API and to Frontend but something went wrong, I couldn’t understand the Ember errors probably because I’m relatively new to Ember/CLI.

So the question: What can be done to improve the speed of this website? It currently takes 4-5 seconds to initially load and about 3 seconds for consequent requests.

From the Chrome’s profile (attached)

I see that the scripting alone takes 2.5 seconds! I could probably figure out how to preload the data (a tiny json), but I have no idea what to do about that scripting thing.

Thank you in advance.